Merges the full hardened stack (#788 closets, #789 entity/BM25/diary,
#790 tunnels) and reimplements the drawer-grep feature in a way that
composes with the chunk-level closet-first search instead of fighting it.
## Background
The original PR added "drawer-grep" on top of the pre-hardening closet
code that returned whole-file blobs. My #788 hardening changed that
path to return *chunk-level* hits by parsing each closet's
``→drawer_id`` pointers and hydrating exactly those drawers. That made
the original drawer-grep grep-over-all-drawers logic redundant — the
closet already points at the relevant chunk.
What remained valuable from the original PR was the *context expansion*
idea: a chunk boundary can clip a thought mid-stride (matched chunk
says "here's a breakdown:" and the breakdown lives in the next chunk),
so callers want ±1 neighbor chunks for free rather than a follow-up
get_drawer call.
## Change
New ``_expand_with_neighbors(drawers_col, doc, meta, radius=1)`` helper
in searcher.py:
* Reads ``source_file`` + ``chunk_index`` from the matched drawer's
metadata.
* Fetches the ±radius sibling chunks in a SINGLE ChromaDB query using
``$and + $in`` — no "fetch all drawers for source" blowup.
* Sorts retrieved chunks by chunk_index, joins with ``\n\n``.
* Does a cheap metadata-only second query to compute ``total_drawers``
so callers know where in the file they landed.
* Graceful fallback to the matched doc alone on any ChromaDB failure or
missing metadata — search never breaks because expansion failed.
``_closet_first_hits`` now calls this helper and tags each hit with
``drawer_index`` + ``total_drawers``. Hit shape stays consistent with
the direct-search path (both still carry ``matched_via``) so callers
can't tell which path produced a given hit except via that field.
## Tests
6 new cases in TestDrawerGrepExpansion:
* neighbors returned in chunk_index order (not hash order)
* edge case: matched chunk at index 0 — only next neighbor surfaces
* edge case: matched chunk at last index — only prev neighbor surfaces
* edge case: 1-drawer file — returns just the matched doc
* missing/non-int chunk_index metadata — graceful fallback
* end-to-end via ``search_memories`` — closet-first hit carries
drawer_index, total_drawers, and includes ±1 neighbors
761/761 suite pass; ruff + format clean on CI-pinned 0.4.x.
Merge resolutions: miner.py kept develop's purge+NORMALIZE_VERSION;
searcher.py dropped the old whole-file-blob block entirely in favor of
rebuilding context expansion on top of ``_closet_first_hits``;
test_closets.py took develop's 47-test baseline and appended
TestDrawerGrepExpansion.
Igor Lins e Silva
e9201fb617