feat(warp): include session_name in structured payloads

[nscrdev]

Problem

The Warp sidebar shows the cwd path twice for a Claude Code session — once as the title and once as the subtitle — because the structured payloads only carry session_id, cwd, and project. The human-readable session name never reaches Warp. This is the data half of #34 (tab title not updated on /rename).

Change

Claude Code maintains a session registry at ~/.claude/sessions/<pid>.json — one file per running session containing sessionId, name, updatedAt, etc. The name field is kept current on /rename.

build_payload() now looks up the session name by session_id in that registry and includes it as session_name on every warp://cli-agent payload. Since the lookup happens at payload-build time, any payload sent after a /rename (next prompt submit, tool use, or stop) carries the new name.

Details:

• Fail-soft: missing registry dir, no matching session, or malformed JSON all yield an empty session_name — hooks never break.
• If duplicate sessionId entries exist (stale files), the most recently updated entry wins (max_by(.updatedAt)).
• One extra jq invocation per payload; respects CLAUDE_CONFIG_DIR, and CLAUDE_SESSIONS_DIR overrides the registry location for tests.
• Field is always present (empty string when unknown), additive to protocol v1.
• Tests added for hit / miss / missing id / missing dir; suite passes (the 2 pre-existing failures on Windows/MSYS path conversion are unrelated and fail identically on main).

Warp-side note

This PR only supplies the data. To fix the duplicated sidebar line, Warp's sidebar renderer should prefer session_name over cwd for the title row when the field is non-empty.

🤖 Generated with Claude Code