feat: add Claude Code support

[davidrobertson]

Summary

• add native Claude Code packaging, four-event live capture, MCP integration, and user-scoped plugin lifecycle commands
• preserve shared storage, sanitization, retrieval provenance, and all existing Codex, Cursor, VS Code, Copilot, and Kiro behavior
• fix Codex MCP startup by using the native plugin working directory instead of an unexpanded ${PLUGIN_ROOT} argument
• document Claude installation, live-only capture limits, refresh, inspection, and removal

Why

Agent LCM supported five coding-agent harnesses but could not capture or retrieve Claude Code sessions. Claude Code now has a native plugin package that reuses Agent LCM's existing sanitized inbox, daemon, raw log, index, and MCP paths without adding a historical transcript importer or a second storage implementation.

Validation

• npm run typecheck
• npm test — 381 passed, 0 failed, 2 platform-only skips
• npm run smoke
• npm run release:check
• fresh-cache package and installed-artifact QA for Codex and Claude MCP manifests
• authenticated Claude Code run: MCP connected, lcm_health succeeded, all four hooks fired, and events persisted in an isolated store
• fresh authenticated Codex run: agent-lcm/lcm_health completed with structured health after npm install and Codex cache refresh
• native lifecycle QA for Claude plus regression coverage for Codex, Cursor, VS Code, Copilot, and Kiro
• macOS, Windows, and quality CI passed at 7d888b8eac464943d055633f1aba0f824096de34

Notes

• Claude support is live capture only; this PR does not add a historical Claude transcript importer.
• No release or version bump is included.
• This PR remains draft and must not be merged yet.