Event subscriptions, reprocessing, text-only search fallback, name-based lookup, and 8 new REST endpoints. Ready for Core integration.

• Event Subscription: vault.subscribe(callback) for real-time mutation events (CREATE, UPDATE, DELETE, LIFECYCLE_TRANSITION). Sync and async callbacks. 5-second timeout, 100-subscriber cap, error isolation. Returns unsubscribe function.
• Reprocess: vault.reprocess(resource_id) re-chunks and re-embeds when embedding models change. Preserves content, regenerates chunks.
• Text-Only Search Fallback: vault.search() auto-degrades to text-only when no embedder is configured. Search works day one.
• Find By Name: vault.find_by_name(name) case-insensitive lookup across the vault.
• 8 New REST Endpoints: reprocess, grep, find by name, diff, get multiple, adversarial status, import, batch retrieval. 30 total endpoints.

• assert replaced with if/raise (survives -O bytecode)
• Async callback timeout (5s) prevents event loop blocking
• Subscriber cap (100) prevents memory exhaustion
• Adversarial status allowlist validation
• Import endpoint path traversal guard
• Resource ID type coercion
• RBAC enforcement on all new methods
• Score: 100/100 (bandit clean, pip-audit clean)

• 117 new tests (871+ total)
• 8 new REST endpoints (30 total)
• 3 docs updated (api-reference, fastapi, streaming)
• 0 breaking changes