2.3.0 — the index train: local-first recall index, incremental sweep, stemming + alias expansion

One schema-bump release (recall-index schema 3, entity-index schema 2; old
recall indexes rebuild automatically, no vault migration):

- Local-first recall index: the live BM25 index lives in the machine state dir
  (keyed by endpoint hash); capture's upkeep is a zero-network atomic file
  write, no advisory lock — replacing the O(vault) GET/PUT-whole-index round
  trip per write. The vault copy is a snapshot (sweep + session-end) used to
  seed fresh machines / catch up after another client swept
  (ECHO_RECALL_SYNC_HOURS, default 24). The read path never PUTs the vault.
- Incremental sweep: entity + recall meta carry 16-char content hashes;
  `sweep --fast` fetches only new/gone/hash-missing notes plus a rotating
  weekday shard (--all-shards forces everything); deletions drop from both
  indexes; index-only so no --apply gate. `load` auto-runs it past
  ECHO_FAST_SWEEP_DAYS (7); doctor reports index freshness. Obsidian-side
  edits now reach the indexes without manual maintenance.
- Stemming + alias expansion: echo_stem.py (conservative Porter-lite, unit-
  tested families + over-stemming guards) applied at index AND query time;
  a query fuzzy-matching an entity folds its title/alias vocabulary into the
  BM25 query at half weight — expansion can only boost docs containing the
  terms. capture hashes the note's FINAL content (auto-link reordered first).

Eval gold set 8 -> 14 queries (6 paraphrases): recall@5/MRR 1.00/1.00 vs
keyword baseline 0.75/0.79. +3 unit tests, +10 e2e; test harnesses now isolate
ECHO_STATE_DIR. All seven suites green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

echo-memory.plugin.src/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "echo-memory",
-  "version": "2.2.0",
+  "version": "2.3.0",
   "homepage": "https://git.alwisp.com/jason/echo",
   "repository": "https://git.alwisp.com/jason/echo",
   "description": "Persistent memory via the ECHO Obsidian vault over the Obsidian Local REST API. Cross-platform Python client: one-call capture/resolve/recall/link/triage over an entity index, hybrid BM25 + graph recall spanning entities + sessions/journal (recency/status-aware), a pre-write duplicate gate, complete-frontmatter capture, session hooks that self-fire load/reflect, offline write-ahead queue, lock-guarded concurrency, linter-enforced routing, and /echo-* commands.",