merge: develop + harden closet layer for production

Merges develop (#820 version sync, #785 strip_noise + NORMALIZE_VERSION,
#784 file locking) and addresses six concerns surfaced during PR review
of the closet feature:

1. Closet append-on-rebuild bug — upsert_closet_lines used to APPEND to
   existing closets (mismatched the doc's "fully replaced" promise). With
   NORMALIZE_VERSION rebuilds on develop, this would have stacked stale
   v1 topics on top of fresh v2 content forever. Fix:
   - Drop the read-and-append branch from upsert_closet_lines (now a pure
     numbered-id overwrite).
   - Add purge_file_closets(closets_col, source_file) helper that wipes
     every closet for a source file by where-filter.
   - process_file calls purge_file_closets before upsert on every mine,
     mirroring the existing drawer purge.

2. Searcher returned whole-file blobs from the closet path while the
   direct path returned chunk-level drawers. Refactored:
   - _extract_drawer_ids_from_closet parses the `→drawer_a,drawer_b`
     pointers out of closet documents.
   - _closet_first_hits hydrates exactly those drawer IDs (chunk-level),
     not collection.get(where=source_file) (which returned everything).
   - Same hit shape as direct-search path; both now carry matched_via.

3. max_distance was bypassed on the closet path. Now applied per-hit;
   when every closet candidate gets filtered, _closet_first_hits returns
   None and the caller falls through to direct drawer search.

4. Entity extraction caught sentence-starters like "When", "The",
   "After" as proper nouns. Added _ENTITY_STOPLIST (~40 common false
   positives + day/month names + role words). Real names like Igor /
   Milla still survive — covered by tests.

5. CLOSETS.md drifted from the code (claimed "replaced via upsert" but
   code appended; claimed BM25 hybrid that doesn't exist; claimed a
   10K char hydration cap that wasn't enforced). Rewritten to describe
   what actually ships, with explicit notes on the BM25 / convo-closet
   follow-ups.

6. Zero tests for ~250 lines. Added tests/test_closets.py with 17 cases:
   - build_closet_lines: pointer shape, header extraction, stoplist
     filtering (with regression case for "When/After/The"), real-name
     survival, fallback-line guarantee, drawer-ref slicing.
   - upsert_closet_lines: pure overwrite semantics (regression for the
     append bug), char-limit packing without splitting lines.
   - purge_file_closets: scoped to source_file, doesn't touch others.
   - End-to-end miner rebuild: re-mining a file with fewer topics fully
     purges leftover numbered closets from the larger first run.
   - _extract_drawer_ids_from_closet: parsing + dedup edge cases.
   - search_memories closet-first: fallback when empty, chunk-level
     hits with matched_via, no whole-file glue, max_distance enforced.

Merge resolutions: miner.py imports combined NORMALIZE_VERSION/mine_lock
from develop with the closet helpers from this branch. process_file
auto-merged cleanly (closet block sits inside develop's lock body).

724/724 tests pass. ruff + format clean under CI-pinned 0.4.x.

docs/CLOSETS.md

@@ -32,13 +32,11 @@ Topics are never split across closets. If adding a topic would exceed 1,500 char
 
 ### When do closets update?
 
-When a file is re-mined (content changed), its drawers are replaced and new closets are built from the fresh content. The old closet content is replaced via upsert.
+When a file is re-mined (content changed, or `NORMALIZE_VERSION` was bumped), the miner first deletes every closet for that source file (`purge_file_closets`) and then writes a fresh set. Stale topics from the prior mine are gone — closets are always a snapshot of the current content, never an accumulation across runs.
 
 ### What about stale topics?
 
-If a file's content changes and a topic no longer exists, the closet is rebuilt entirely from the new content — stale topics are gone. Closets are tied to source files, not to individual topics.
-
-If you add content to an existing file (e.g., a daily diary growing throughout the day), new topics are appended to the existing closet until the 1,500-char limit, then a new closet is created.
+There are no stale topics: each re-mine is a clean rebuild for that source file. If a file gets larger and produces fewer or more closets than last time, the leftover numbered closets from the larger run are still purged because the delete is done by `source_file`, not by ID.
 
 ### Do closets survive palace rebuilds?
 
@@ -49,31 +47,42 @@ Closets are stored in the `mempalace_closets` ChromaDB collection alongside `mem
 ```
 Query → search mempalace_closets (fast, small documents)
          ↓
-    top closet hits → extract drawer IDs from pointer lines
+    top closet hits → parse `→drawer_id_a,drawer_id_b` pointers
          ↓
-    fetch drawers from mempalace_drawers (full verbatim content)
+    fetch exactly those drawers from mempalace_drawers (verbatim content)
          ↓
-    BM25 hybrid re-rank (keyword match + vector similarity)
+    apply max_distance filter
          ↓
-    return results to user
+    return chunk-level results (same shape as direct search)
 ```
 
-If no closets exist (palace created before this feature), search falls back to direct drawer search. Closets are created on next mine.
+Hits carry `matched_via: "closet"` (or `"drawer"` for the fallback path) plus a `closet_preview` field showing the line that surfaced them.
+
+If no closets exist (palace created before this feature) — or all closet hits get filtered out by `max_distance` — search falls back to direct drawer search. Closets are created on next mine.
+
+> **BM25 hybrid re-rank** is on the roadmap (deferred to a follow-up PR alongside generic `LLM_*` env-var support); the current closet search ranks purely by ChromaDB cosine distance against the closet text.
 
 ## Limits
 
 | Setting | Value | Reason |
 |---------|-------|--------|
-| Max closet size | 1,500 chars | Leaves buffer under ChromaDB's working limit |
+| Max closet size | 1,500 chars (`CLOSET_CHAR_LIMIT`) | Leaves buffer under ChromaDB's working limit |
+| Source content scanned | 5,000 chars (`CLOSET_EXTRACT_WINDOW`) | Caps regex extraction cost on long files; back-of-file content is currently invisible to closet extraction (tracked for follow-up) |
 | Max topics per file | 12 | Keeps closets focused |
 | Max quotes per file | 3 | Most relevant only |
-| Max entities per pointer | 5 | Top names by frequency |
-| Max response chars | 10,000 | Prevents hydration blowup on large files |
+| Max entities per pointer | 5 | Top names by frequency, after stoplist filtering |
 
 ## For developers
 
 Closet functions live in `mempalace/palace.py`:
 - `get_closets_collection()` — get the closets ChromaDB collection
 - `build_closet_lines()` — extract topics/entities/quotes into pointer lines
-- `upsert_closet_lines()` — write lines to closets respecting the char limit
-- `CLOSET_CHAR_LIMIT` — the 1,500 char limit constant
+- `upsert_closet_lines()` — write lines to closets respecting the char limit (overwrites existing IDs; does not append — call `purge_file_closets` first when re-mining)
+- `purge_file_closets()` — delete every closet for a given source file before rebuild
+- `CLOSET_CHAR_LIMIT` / `CLOSET_EXTRACT_WINDOW` — size constants
+
+The closet-first search path lives in `mempalace/searcher.py`:
+- `_extract_drawer_ids_from_closet()` — parse `→drawer_a,drawer_b` pointers out of a closet document
+- `_closet_first_hits()` — query closets, parse pointers, hydrate matching drawers, return chunk-level hits or `None` to fall back
+
+Note: only the project miner (`miner.py::process_file`) builds closets today. Conversation-mined wings (Claude Code JSONL, ChatGPT export, etc.) will keep using direct drawer search via the searcher fallback until the convo-closet PR lands.