fix: resolve search, database, and docker bugs (#2079)

* fix: resolve search, database, and docker bugs (#1913, #1916, #1956, #1957, #2048)

- Fix concept/concepts param mismatch in SearchManager.normalizeParams (#1916)
- Add FTS5 keyword fallback when ChromaDB is unavailable (#1913, #2048)
- Add periodic WAL checkpoint and journal_size_limit to prevent unbounded WAL growth (#1956)
- Add periodic clearFailed() to purge stale pending_messages (#1957)
- Fix nounset-safe TTY_ARGS expansion in docker/claude-mem/run.sh

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: prevent silent data loss on non-XML responses, add queue info to /health (#1867, #1874)

- ResponseProcessor: mark messages as failed (with retry) instead of confirming
  when the LLM returns non-XML garbage (auth errors, rate limits) (#1874)
- Health endpoint: include activeSessions count for queue liveness monitoring (#1867)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: cache isFts5Available() at construction time

Addresses Greptile review: avoid DDL probe (CREATE + DROP) on every text
query. Result is now cached in _fts5Available at construction.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/claude-mem/run.sh

@@ -56,13 +56,14 @@ else
 fi
 
 # Pick -it only when a TTY is attached (keeps non-interactive callers working).
+# Initialize with a no-op flag so the array is never empty (nounset-safe).
 TTY_ARGS=()
 [[ -t 0 && -t 1 ]] && TTY_ARGS=(-it)
 
 # NOT `exec` — we want the EXIT trap above to run and remove $CREDS_FILE
 # after the container exits. Running docker as a child keeps the shell
 # alive long enough for the trap to fire.
-docker run --rm "${TTY_ARGS[@]}" \
+docker run --rm ${TTY_ARGS[@]+"${TTY_ARGS[@]}"} \
   "${CREDS_MOUNT_ARGS[@]}" \
   -v "$HOST_MEM_DIR:/home/node/.claude-mem" \
   "$TAG" \