# q42 Format Internal Draft **Status:** Internal draft (implementation converged on v3 unified volume, 2026-06-11; indexes, publication gates, and five-field ECC recorded 2026-08-15) **Date:** 2026-06-09 (revised 2026-08-15 — v3 indexes + publication) **Purpose:** Freeze the current implementation reality of the `q42` container family before any external standardization work begins. This revision **does not relax** the 48-byte NQuin, 40,960-byte SuperBlock, 256-byte header, v3-only new writes, or 42 MB SlgArena ceiling. It records indexes, ECC, and publication rules that the writer already enforces. ## Draft Headings 1. Block Architecture Mandate 2. Capability Envelope Migration 3. Scope 4. Current Conclusion 5. Current Implementation Reality 6. Terminology 7. Canonical Physical Layout 8. Canonical Artifact Set 9. Legacy Profiles (read-only compatibility) 10. Contradictions Resolved or Remaining 11. Proposed Canonical Rules 12. Open Questions 13. Remaining Cleanup Mandate ## 1. Block Architecture Mandate The `q42` family is defined as a hierarchically indexed, block-oriented format, not as a single continuous stream-compressed archive. ### 1.1 What is deprecated The following models are deprecated for **new writes**: - treating `.q42` as a raw concatenation of uncompressed SuperBlocks with mandatory `.q42.lex` and `.q42.bidx` sidecars - treating `.q42` as if it were a single continuous framed LZ4 stream (the profile read by `q42_reader.rs`) - emitting a separate `.c.q42` as a distribution artifact. LZ4 SuperBlocks live inside the unified `.q42`. The `.c.q42` extension is obsolete. ### 1.2 What is mandated The storage model is: 1. A `q42` dataset is partitioned into independently addressable 40,960-byte SuperBlocks. 2. Each SuperBlock is the fundamental physical I/O unit. 3. Index lookup determines which block to read before any block payload is decompressed. 4. Compression, when used, is **block-local** (per SuperBlock), not whole-file stream-based. ### 1.3 Index placement (v3 — implemented 2026-06-11) As of 2026-06-11, **new ingest writes a single unified v3 `.q42` volume**: - 256-byte file header (`Q42\0`, version 3) - embedded Q42LEX blob (uncompressed) - embedded BIDX blob (uncompressed) - optional FIDX (per-block subject/predicate/context ranges; flag `0x0008`) - optional PIDX (compact S/P/C postings or measured Bloom; flag `0x0010`) - block directory (16 bytes per block: relative offset, compressed length, uncompressed length) - concatenated LZ4-compressed SuperBlock payloads - optional temporal index section (offset/length in header; `0` if absent) - optional Merkle-DAG history section (offset/length in header; `0` if absent) Implementation: `crates/qualia-core-db/src/q42/q42_volume.rs` and `crates/qualia-core-db/src/q42/volume/`. New writes set `FLAG_PERMISSIVE_COMMONS` (`0x0020`) only for affirmatively catalogued public datasets. `FLAG_SANCTUARY` (`0x0040`) is set for personal, medical, legal, fiduciary, bilateral, or otherwise restricted volumes. Public magnets / web-seeds / IPFS pins **fail closed** unless Commons is set and Sanctuary is clear. See `q42/volume/publication.rs`. v2 files are **hard-rejected** by v3 builds — `verify_version()` returns an error unless version == 3. Use `migrate_v2_to_v3()` (one-pass, in-place rewrite) before opening. v3 adds no byte-alignment changes to the SuperBlock or NQuin layouts. Legacy v1 sidecars (`.q42.lex`, `.q42.bidx`) and raw SuperBlock streams remain **readable** via `Q42Lexicon::load_for_q42()` and related fallbacks, but are no longer emitted by `qualia-cli ingest`. ## 2. Capability Envelope Migration The capability envelope namespace must be disentangled from generic `.chk` usage. ### 2.1 Migration decision This draft recommends: - rename QCHK artifacts from `.chk` to `.qchk` - treat `.qchk` as the canonical extension for Qualia capability envelopes - keep `QCHK` magic bytes as the in-file discriminator until a later revision changes the envelope format ### 2.2 Why this migration is required The current `.chk` collision creates avoidable ambiguity with other checkpoint and chunk formats, including the CogAI text path already documented in the repo. This draft therefore treats `.chk` support for QCHK as legacy compatibility, not the long-term public name. ### 2.3 MIME and media-type direction For future external standardization, the envelope should receive its own media type rather than borrowing generic checkpoint naming. Initial candidates to evaluate later: - `application/vnd.qualia.qchk` - `application/vnd.qualia.chk+cbor` This draft does not yet choose between them, but it mandates that the public identifier be Qualia-specific. ## 3. Scope This draft covers the Layer 0 data artifacts currently exposed by QualiaDB: - unified v3 `.q42` volumes (canonical for new ingest) - legacy v1 raw SuperBlock `.q42` streams (read compatibility) - legacy `.q42.lex` and `.q42.bidx` sidecars (read compatibility) - leftover `.c.q42` framed LZ4 profile (read-only; do not emit) - companion `.qualia` vault-manifest semantics as they relate to the artifact family entry point - related capability-envelope migration decisions required to avoid namespace collisions during standards work This draft does not define: - `did:q42` - Webizen protocol behavior - sync handshakes - the full QCHK payload semantics ## 4. Current Conclusion This draft adopts the following model as of 2026-06-11: 1. **Unified v3 `.q42`** is the canonical on-disk container for new datasets. v2 volumes must be migrated via `migrate_v2_to_v3()` before use. 2. **Embedded Q42LEX and BIDX** replace sidecars for new writes. 3. **Block-local LZ4** compresses each SuperBlock inside the volume; there is no separate mandatory compressed transport file. 4. **`.c.q42` is obsolete.** New ingest MUST NOT emit it. A leftover file may still be readable as legacy framed transport; it is not a distribution twin of a v3 volume. 5. **`q42_reader.rs`** reads the legacy framed LZ4 transport profile only; it does not read v3 unified volumes. Use `Q42Volume` / `docs/playground/vfs.js`. 6. **QCHK capability envelopes** should migrate from `.chk` to `.qchk`. 7. **v3 header extensions** add: temporal index section, SHA-256 Merkle root, assertion timestamp, and Merkle-DAG history section (see §7 for layout). ## 5. Current Implementation Reality The repo now converges on one primary write path and several read fallbacks: | Path | Role | Module | |------|------|--------| | v3 unified volume write | canonical ingest output | `q42/q42_volume.rs`, `q42/volume/stream_writer.rs`, `write_quins.rs` | | v3 unified volume read | mmap open, lex view, BIDX/FIDX/PIDX, block decompress | `Q42Volume`, `docs/playground/vfs.js` | | inspect / verify / magnet | CLI + Studio Volume Manager | `q42/volume/{inspect,verify,publication,magnet}.rs` | | v2 → v3 migration | one-pass header upgrade | `q42_volume::migrate_v2_to_v3()` / `qualia q42 compact` | | v1 sidecar lex read | legacy WordNet / Index trees | `Q42Lexicon::load`, `load_for_q42` | | v1 raw SuperBlock read | legacy aligned streams | `storage.rs` | | framed LZ4 transport read | leftover `.c.q42` only | `q42_reader.rs` | Writers: - `ingest_ntriples`, `ingest_rdf_xml` → `write_unified_volume()` - external sort (`ingest_chk`, `ingest_cbor`, import merge) → `UnifiedVolumeBuilder` Readers: - `chat_ontology`, neuro-symbolic sieve → `Q42Lexicon::load_for_q42()` (v3 embedded lex; v1 sidecar only as fallback) - daemon / graph / chat compact / checkpoint → `write_sorted_quins_volume` / `Q42Volume` - GitHub Pages VFS → `docs/playground/vfs.js` (`parseQ42Header`, FIDX/PIDX flags) ## 6. Terminology ### NQuin The atomic record unit is `NQuin`. - Size: 48 bytes - Layout: six little-endian `u64` fields - Fields: `subject`, `predicate`, `object`, `context`, `metadata`, `parity` Important clarification: - The current implementation is not a "42+6 byte split". - It is a full 48-byte structure with a dedicated 64-bit `parity` field. ### QualiaSuperBlock The canonical physical storage page is `QualiaSuperBlock`. - Size: 40,960 bytes - Alignment: 4,096 bytes (logical page; v2 stores LZ4-compressed payloads) - Structure: 160-byte header + 40,800-byte quin ledger (850 × 48 bytes) ### Unified v3 volume - Single `.q42` file with file magic `Q42\0`, version `3` - Flags (u16): - `0x0001` `FLAG_BLOCKS_LZ4` — SuperBlocks are LZ4-compressed - `0x0002` `FLAG_OBJECT_SORTED` — ingest sorted by object hash - `0x0004` `FLAG_VOLUME_ROOT` — multi-file volume set root + manifest - `0x0008` `FLAG_FIELD_RANGES` — FIDX present - `0x0010` `FLAG_FIELD_POSTINGS` — PIDX present - `0x0020` `FLAG_PERMISSIVE_COMMONS` — public catalog (required for magnets) - `0x0040` `FLAG_SANCTUARY` — Sanctuary / restricted; public magnets denied - Extended header adds: temporal index section, SHA-256 Merkle root (streaming chain over SuperBlock payloads), assertion timestamp, Merkle-DAG history section, optional natural-person / software-agent DID offsets, FIDX/PIDX pointers in `_reserved` ### Embedded sections (v3) - **Q42LEX**: same binary layout as the obsolete `.q42.lex` sidecar - **BIDX**: same binary layout as the obsolete `.q42.bidx` sidecar - **FIDX**: `FIDX` magic, 16-byte header, 48-byte per-block S/P/C range entries - **PIDX**: compact postings / Bloom for S/P/C; optional, flag-gated ### Legacy sidecars (v1, read-only for new ingest) - `.q42.lex`: reverse hash-to-string dictionary (standalone file) - `.q42.bidx`: block-range index (standalone file) ### Transport profile (obsolete) - `.c.q42`: leftover framed LZ4 quin stream. Not a v3 twin. Do not emit. ### Vault manifest - `.qualia`: high-level vault or collection descriptor - expected to reference one or more unified v3 `.q42` artifacts ## 7. Canonical Physical Layout ### `NQuin` ```text Offset Size Field 0 8 subject 8 8 predicate 16 8 object 24 8 context 32 8 metadata 40 8 parity ``` All fields are little-endian. Producers **MUST** set `parity = subject ^ predicate ^ object ^ context ^ metadata` (`NQuin::calculate_parity`). `verify_ecc_parity()` returns true only when that five-field fold matches. A four-field fold (metadata omitted) is a **verify Fail** on current volumes. This is stricter than earlier draft prose that omitted `metadata`. ### `QualiaSuperBlock` ```text Offset Size Field 0 8 block_sequence_id 8 8 storage_owner_did 16 8 active_quin_count 24 4 validation_checksum 28 4 hardware_profile_flags 32 8 fea_mesh_index_id 40 120 layout_padding 160 40800 quin_ledger[850] ``` Properties: - `size == 40960`, `QUINS_PER_BLOCK == 850` - remaining ledger slots are zero-filled - `fea_mesh_index_id` is a reserved attachment point, not proof that dense geometry is stored inside Q42. As of 2026-07-03, `q42_volume::encode_superblock()` leaves this field zero and the OBJ/STL/GLB ingest path writes semantic mesh facts only. The planned computational-asset compiler will either wire this field to a versioned analysis-mesh sidecar or supersede it with an explicit Q42 relationship that can address multiple meshes and fidelity tiers. ### Unified v3 volume layout ```text [0..256) Q42VolumeHeader [lex_offset ..) Q42LEX blob (see §8) [bidx_offset ..) BIDX blob (see §8) [block_dir_offset ..) block_count × BlockDirectoryEntry (16 bytes each) [data_offset ..) concatenated LZ4 payloads (lz4_flex prepend_size) BlockDirectoryEntry: [0..8] rel_offset u64 LE — byte offset from data_offset [8..12] comp_len u32 LE [12..16] uncomp_len u32 LE — always 40960 for current ingest ``` Header fields (little-endian, v3 — 256 bytes total): ```text [0..4] magic "Q42\0" [4..6] version u16 = 3 (v2 hard-rejected; use migrate_v2_to_v3()) [6..8] flags u16 [8..16] lex_offset u64 [16..24] lex_length u64 [24..32] bidx_offset u64 [32..40] bidx_length u64 [40..48] block_dir_offset u64 [48..56] block_dir_length u64 [56..64] data_offset u64 [64..72] data_length u64 [72..80] block_count u64 [80..84] block_size u32 = 40960 [84..88] quins_per_block u32 = 850 — v3 extensions (carved from former reserved bytes) — [88..96] temporal_index_offset u64 (0 if no temporal index) [96..104] temporal_index_length u64 [104..136] merkle_root [u8; 32] SHA-256 of DAG root node [136..144] assertion_timestamp u64 ms since Unix epoch (last write) [144..152] dag_root_offset u64 (0 if no DAG history) [152..160] dag_root_length u64 [160..168] natural_person_did_offset u64 [168..176] software_agent_did_offset u64 [176..256] _reserved [u8; 80] [176..192] volume-set manifest offset/length when FLAG_VOLUME_ROOT [192..208] FIDX offset/length when FLAG_FIELD_RANGES [208..224] PIDX offset/length when FLAG_FIELD_POSTINGS ``` Detection: `is_v2_volume()` checks magic `Q42\0` at offset 0. `verify_version()` rejects anything other than version 3; to open a v2 file call `migrate_v2_to_v3()` first. Ingest sorts all quins by **object hash** before chunking so BIDX ranges are ascending and binary-searchable. ## 8. Canonical Artifact Set ### Unified v3 `.q42` (canonical) Recommended meaning for all new datasets: - single self-contained file, version 3 - embedded lexicon and block index - LZ4-compressed SuperBlocks - optional temporal index section (bi-temporal PROV-O quins) - optional Merkle-DAG history section (`DagNode` chain from `git_bridge.rs`) - SHA-256 Merkle root over the current DAG tip - memory-mapped via `Q42Volume::open()` Matches: - `crates/qualia-core-db/src/q42_volume.rs` - `crates/qualia-core-db/src/git_bridge.rs` (`DagStore::serialize()`) - `crates/qualia-cli/src/ingest.rs` - `scripts/fetch_wordnet.sh` (outputs `wordnet.q42` only) ### `.p64` weight container (AOT LLM) The byte-accurate normative layout, including all fixed-record offsets, flags, tokenizer encoding, manifold records, checksums, and reader validation rules, is specified separately in [`p64-weight-container-standard.md`](p64-weight-container-standard.md). A **separate** artifact from the semantic graph `.q42` above — it carries an **independent section magic** (`b"p64\0"`, never collides with `Q42\0`). It is the Ahead-Of-Time-compiled home for an LLM's weights, so the engine boots **zero-parse** instead of re-parsing a GGUF on every load. Produced by the AOT compiler `q42::p64_weight::compile_gguf_to_p64` (also reachable from WASM), cached in OPFS, and consumed by the resident-weight loader (`P64TensorIndex::from_p64` → GPU arenas). **Inference runs from the `.p64`; the source GGUF is never re-touched.** > **Producer / runtime boundary.** The **engine runs the `.p64`**. The WGSL *forge* transcodes > GGUF → `.p64` and certifies the GPU kernels against a CPU oracle — it does **not** run inference, and > throughput (tok/s) is the engine's, not the forge's. Unlike the semantic `.q42`, the weight container carries **no `NQuin` scaffold**: the 48-byte declarative `q42` quin manages truth/provenance, while the 64-byte-aligned `p64` manages pure mathematical inference with zero-copy relative (WASM-native) pointers. ```text P64WeightHeader (64 B, #[repr(C, align(64))], little-endian) magic "p64\0" u8[4] — distinguishes from the semantic .q42 (Q42\0) version u16 = 3 flags u16 — endianness (P64_FLAG_LITTLE_ENDIAN) — 32-bit RELATIVE offsets (WASM-native; bytes from start of file) — role_table_offset u32 — tensor → semantic role map tensor_table_offset u32 — P64TensorEntry descriptor table tokenizer_offset u32 — embedded tokenizer (self-contained; no GGUF needed) hparams_offset u32 — model hyperparameters string_table_offset u32 — centralized string pool checksum_offset u32 — CRC-32C tamper-evidence manifold_table_offset u32 — 10-D ManifoldCoordinate10D table (64 B/entry) tensor_count u32 page_size u32 — blob alignment (default 16 KB; page_log2 = 14) reserved u8[20] — pads to exactly 64 B Manifest tensor_count × P64TensorEntry (64 B each) role, dtype, rank, dims, relative blob offset/length. Roles (P64_ROLE_*): ATTN_K 0, ATTN_V 1, ATTN_Q 2, ATTN_OUTPUT 3, FFN_GATE 4, FFN_UP 5, FFN_DOWN 6, ATTN_NORM 7, FFN_NORM 8, TOKEN_EMBD 9, OUTPUT 10, OUTPUT_NORM 11; UNKNOWN 0xFFFE (preserved byte-for-byte, unconsumed), LAYER_GLOBAL 0xFFFF (non-layer tensor). Tensor blobs — opaque, contiguous, page-aligned (page_log2) quantized bytes for single-fetch mmap / zero-copy WebGPU bind. ``` Matches `crates/qualia-core-db/src/q42/p64_weight.rs` (`P64WeightHeader`, `P64TensorEntry`, `compile_gguf_to_p64`, `P64TensorIndex::from_p64`, `P64_ROLE_*`). Integrity is table-less CRC-32C; the 16 KB page alignment lets the resident-weight upload map blobs straight into the GPU arenas. The semantic `.q42` and the weight `.p64` are siblings: both cache-aligned, distinct magics, distinct jobs. > **Historical note.** A pre-P64 `Q42W` weight layout (144-byte `Q42WeightHeader`, NQuin-scaffolded, > magic `"Q42W"`) preceded this container; it is **superseded** by `.p64` and retained only as migration > test fixtures (`q42::p64_weight` tests). ### Embedded Q42LEX layout Same as legacy `.q42.lex`: ```text Header (32 bytes) [0..8] magic "Q42LEX\0\0" [8..16] entry_count u64 LE [16..24] strings_offset u64 LE [24..32] version u64 LE Index (entry_count × 16 bytes, sorted by hash) [0..8] hash u64 LE [8..16] str_off u64 LE String blob repeated: u16 LE length + UTF-8 bytes ``` ### Embedded BIDX layout Same as legacy `.q42.bidx`: ```text Header (16 bytes) [0..4] magic "BIDX" [4..8] version u32 LE = 1 [8..12] block_count u32 LE [12..16] reserved u32 LE = 0 Index (block_count × 16 bytes) [0..8] min_hash u64 LE — min object hash in block [8..16] max_hash u64 LE — max object hash in block ``` BIDX indexes **object-hash ranges** (not subject-hash). This matches ingest, `Q42Volume::bidx_blocks_for_hash()`, and the intended literal lookup pattern `?s ?p "literal"`. ### Legacy raw v1 `.q42` Historical profile still readable: ```text .q42 file = N × QualiaSuperBlock (40,960-byte stride, uncompressed) ``` Requires separate `.q42.lex` and `.q42.bidx` sidecars for full retrieval. ### Legacy `.c.q42` transport (do not emit) Historical framed profile. Browser Pages now demand-page **unified v3** volumes (`vfs.js`). A leftover `.c.q42` may still decode through `q42_reader.rs`. ```text Per chunk: [0..8] block_id u64 LE [8..12] comp_len u32 LE [12..16] uncomp_len u32 LE [16..] payload lz4_flex::compress_prepend_size output ``` ### `.qualia` Vault or collection manifest — references `.q42` data files. For v3 volumes, lexicon and block index are embedded; manifest sidecar pointers are optional legacy hints only. ## 9. Legacy Profiles (read-only compatibility) The engine retains read paths for: 1. **v1 raw SuperBlock stream** + `.q42.lex` + `.q42.bidx` 2. **Framed LZ4 transport** (`.c.q42` or mislabeled `.q42`) via `q42_reader.rs` 3. **Pre-v2 WordNet trees** under `Local_LIbraries/wordnet/` until re-ingested New ingest MUST NOT emit v1 sidecars. Re-ingest with `qualia-cli ingest` or `scripts/fetch_wordnet.sh` to upgrade. ## 10. Contradictions Resolved or Remaining ### 10.1 Resolved: single-file vs sidecar index **Resolved (2026-06-09):** v2 embeds lex + BIDX. Sidecars are legacy read-only. ### 10.2 Resolved: file-level magic and version **Resolved:** v3 uses magic `Q42\0` and version `3` at offset 0. v2 files are hard-rejected by v3 builds; `migrate_v2_to_v3()` upgrades the 168-byte reserved region to the v3 extended header (temporal, merkle_root, assertion_timestamp, DAG section pointers). ### 10.3 Resolved: compression model **Resolved:** block-local LZ4 inside the volume. Whole-file stream compression is legacy transport only. ### 10.8 Resolved: v3 temporal and DAG header fields (2026-06-11) **Resolved:** v3 carves six new fields from the former `_reserved` region (bytes 88–159): - `temporal_index_offset/length` — byte range of the optional temporal index - `merkle_root [u8;32]` — SHA-256 of the current Merkle-DAG tip - `assertion_timestamp u64` — last-write wall-clock ms - `dag_root_offset/length` — byte range of the serialized `DagStore` All fields are `0` until the corresponding section is written. v3 builds that read a v3 file with `dag_root_length == 0` simply have no DAG history yet. ### 10.4 Resolved: browser VFS (2026-08-15) `docs/playground/vfs.js` reads unified v3 (`parseQ42Header`, FIDX/PIDX flags, block directory, LZ4 SuperBlocks). Pages boot Schema.org 30.0; WordNet is optional (~127 MB Release asset), not a required sidecar pair. ### 10.5 Remaining: BIDX dimension prose drift Some older architecture docs describe BIDX in terms of subject hash. The implementation and this draft use **object-hash ranges** exclusively unless a future versioned revision changes the index dimension. ### 10.6 Remaining: QCHK extension collision QCHK capability envelopes are still named `.chk` in parts of the repo. Migration to `.qchk` is not yet complete. ### 10.7 Remaining: naming drift `.q42` vs `.qla` Older storage comments still refer to `.qla`. Normalize to `.q42` in future doc sweeps. ## 11. Proposed Canonical Rules 1. **New writes** produce unified v3 `.q42` only (magic `Q42\0`, version 3). v2 files must be migrated with `migrate_v2_to_v3()` before opening. 2. Q42LEX and BIDX blobs inside a v2 volume use the same layouts as legacy sidecars. 3. SuperBlocks inside v2 are LZ4-compressed individually; uncompressed size is always 40,960 bytes per block entry. 4. Ingest sorts quins by object hash before block assignment. 5. BIDX indexes object-hash min/max ranges per block. 6. `.q42.lex` and `.q42.bidx` sidecars are legacy; readers must fall back to them when opening non-v2 files. 7. `.c.q42` MUST NOT be emitted. When a leftover file is present it is legacy framed transport only — never a required twin of a v3 volume. 8. `q42_reader.rs` is legacy transport only — not a canonical v3 reader. 8a. Public magnets fail closed unless `FLAG_PERMISSIVE_COMMONS` is set and `FLAG_SANCTUARY` is clear. Unmarked personal volumes do not become addressable by rewriting a flag. 8b. Quin parity is the five-field XOR. Verify Fail on four-field leftovers. 9. `.qchk` is the target canonical capability-envelope extension. 10. `.qualia` is the vault-manifest extension. 11. SlgArena / hot-path memory budget remains **42 MB**, not whole-file mmap of multi-gigabyte volumes; block fetch decompresses one SuperBlock at a time into caller-supplied buffers. ## 12. Open Questions 1. Should `validation_checksum` remain a real field if `parity` already exists? 2. Should BIDX move to subject-hash ranges in a future v4, or stay object-indexed permanently? (v3 retains object-hash BIDX; this remains open for v4.) 3. Should v3 receive an explicit media type (e.g. `application/vnd.qualia.q42+v3`) before IETF submission? 4. *(Resolved 2026-08-15.)* Playground VFS reads v3 natively. No framed-transport translation step. 5. Which public media type should be chosen for `.qchk`? 6. Should `.qualia` be Turtle-only, or also allow N3 / CBOR-LD projections? 7. Should file association be wired first in the Flutter shell, with Tauri treated as secondary or legacy? ## 13. Remaining Cleanup Mandate 1. [x] Converge ingest on unified v2 volume (`q42_volume.rs`). 2. [x] Embed lex + BIDX; stop emitting sidecars from `qualia-cli ingest`. 3. [x] Wire `Q42Lexicon::load_for_q42()` and sieve lex paths for embedded lex. 4. [x] Simplify `fetch_wordnet.sh` to output single `wordnet.q42`. 5. [x] Update WASM playground VFS for unified v3 volumes (`vfs.js`). 6. [ ] Rename QCHK public references from `.chk` to `.qchk`. 7. [ ] Add canonical test vectors: - one single-block v3 `.q42` with FIDX/PIDX and five-field ECC - one multi-block v3 `.q42` with lex entries - one Commons-flagged volume that may mint a magnet - one Sanctuary volume that MUST fail-closed - one `.qchk` 8. [ ] Propose media types for IETF drafting (`application/vnd.qualia.q42+v3`). 9. [ ] Finalize minimal `.qualia` manifest schema for v3 (sidecar terms omitted). 10. [x] Stay on v3 (R10). Lex LZ4 inside the same file; no v4 fork.