Replace per-call gemini CLI spawning (~10s cold start each time) with
persistent ACP (Agent Client Protocol) subprocess. First call absorbs
the cold start, subsequent calls are near-instant over JSON-RPC stdio.
- Add AcpClient: manages persistent gemini --experimental-acp subprocess
with lazy init, auto-restart on crash/timeout, NDJSON framing
- Add GeminiAcpProvider: LlmProvider wrapper with serial queue for
concurrent calls, same interface as GeminiCliProvider
- Add dispose() to LlmProvider interface + disposeAll() to registry
- Wire provider disposal into mcplocal shutdown handler
- Add status command spinner with progressive output and color-coded
LLM health check results (green checkmark/red cross)
- 25 new tests (17 ACP client + 8 provider)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
