fix(hook): prevent SessionEnd timeout on fresh installs

[blackaxgit]

Summary

Fix "SessionEnd hook failed: Hook cancelled" error on fresh installs caused by Ollama health checks exceeding Claude Code's 1.5s SessionEnd timeout.

Root Cause

Claude Code enforces a 1.5 second timeout on SessionEnd hooks. CLX's handler was calling ollama.is_available() which has a 2-4 second health check timeout — guaranteed cancellation when Ollama isn't running.

Fix

Layered defense ensuring SessionEnd always completes in < 1 second:

1. 1s timeout wrapper — tokio::time::timeout around entire handler, returns Ok(()) on timeout
2. Health cache check — reads file-based health cache before any Ollama calls; skips LLM ops if unavailable
3. Time-budget check — skips embedding generation if > 500ms has elapsed
4. Skip LLM summarization — process_transcript() takes ollama_available flag, returns fallback immediately when false

Files changed

• crates/clx-hook/src/hooks/session_end.rs — timeout wrapper + health cache + time budget
• crates/clx-hook/src/transcript.rs — ollama_available parameter to skip LLM
• crates/clx-hook/src/hooks/pre_compact.rs — updated process_transcript() call signature

Test plan

• All workspace tests pass
• New integration test: SessionEnd completes < 1.5s with unreachable Ollama
• 0 clippy warnings
• Binary built and installed locally

🤖 Generated with Claude Code