v0.3.1

Added

• /status and kernel-lore-mcp status now surface live writer state:
  writer_lock_present, sync_active, and a sync block populated
  from kernel-lore-sync's machine-readable heartbeat file.
• Added kernel_lore_mcp_writer_lock_present and
  kernel_lore_mcp_sync_active gauges to /metrics.
• Added scripts/bench/stress_mcp_multiprocess.py, the async +
  multiprocess soak harness used to pressure-test a hosted box over a
  longer run.

Changed

• kernel-lore-sync now writes state/sync.json while it runs and
  emits explicit operator-facing stage logs for bm25_commit,
  tid_rebuild, path_vocab_rebuild, generation_bump, and
  save_manifest.
• Inline BM25 uses conservative explicit writer defaults instead of
  Tantivy's auto-thread selection. New env knobs:
  KLMCP_BM25_WRITER_THREADS and KLMCP_BM25_WRITER_MEMORY_MB.
• rate_limited and query_timeout now return load-aware in-band
  retry hints. Retry guidance rises when a writer-heavy sync stage is
  active on the same box.

Fixed

• Writer activity detection no longer confuses “lockfile exists” with
  “writer lock is actively held”; status probes now test the live flock
  state.
• The “ingest phase done, then silence for minutes” sync log shape is
  gone; BM25 finalization is visible instead of looking hung.