feat(claude-code): surface Task-tool subagent transcripts in detail panel

[panosAthDBX]

Summary

• Claude Code writes Task-tool subagent transcripts to a nested path — ~/.claude/projects/<encoded>/<session-uuid>/subagents/agent-<id>.jsonl — but ClaudeCodeAgentWatcher only scanned the top-level project dir non-recursively, so every subagent was invisible to the tracker and the detail panel showed just the parent session while 2–3 subagents were running.
• This PR teaches the watcher to descend one level into each Claude Code session-UUID subdir and scan/watch its subagents/ child. Each subagent is emitted as its own thread (threadId = "agent-<id>") under the parent's projectDir, so the tracker stores them as distinct per-session instances and the TUI's existing <For each={agents()}> loop renders them alongside the main session.
• Scoped to session-UUID dirs (8-4-4-4-12 hex) so we don't recurse into unrelated children. Polling + a per-session-dir fs.watch catch late-spawning subagents without requiring all paths to exist at start-up.

Motivation

Running Claude Code with the Task tool (subagents) is increasingly common — long-running research delegations, code exploration, code review agents etc. Today opensessions makes those invisible. The fix is small, isolated to the claude-code watcher, and maps cleanly onto the existing per-thread instance model in tracker.ts.

Details

• New helpers in claude-code.ts: SESSION_UUID_RE, isSessionDirName, scanJsonlDir, watchJsonlDir, watchSessionDirForSubagents, setupSubagentWatchers.
• scanInternal() now walks each project dir, scans top-level .jsonl (main sessions), then iterates session-UUID subdirs and scans <uuid>/subagents/*.jsonl.
• setupWatchers() registers fs.watch for existing subagents/ dirs, and for session dirs without one yet, watches for the subagents/ child being created.
• Header docblock updated to describe the nested layout and the agent-<id>.meta.json sibling files (safely ignored — non-.jsonl).
• Behaviour unchanged for projects that never spawn subagents.

Tests

Added three tests in claude-code-watcher.test.ts:

1. seed — a project with 1 main session + 2 subagent transcripts + a .meta.json noise sibling → 3 distinct threadIds emitted, 1 session; .meta.json ignored.
2. live spawn — subagent dir + file appear after seed → event emitted via the per-session-dir watcher.
3. non-UUID sibling guard — a not-a-session/subagents/agent-bogus.jsonl decoy is ignored; we only recurse into UUID-shaped session dirs.

Full runtime suite: 370 pass / 0 fail (was 367 pass; +3 new). Build clean via bun run build.

Validation

• cd packages/runtime && bun test — 370 pass
• bun run build — clean
• Smoke test against a real ~/.claude/projects/ with two in-flight Task-tool subagents: the watcher emitted both agent-* threadIds alongside the parent UUID, each attributed to the same resolved session. Before the fix: zero subagent threads visible.

Related

Closes the Claude Code half of #24. The pi side was canonicalized in #25; this PR handles the other half of "multi-agent per pane is real and should show up" for the Claude Code watcher specifically.

This pull request and its description were written by Isaac.

[inspect-review]

inspect review

Triage: 18 entities analyzed | 0 critical, 0 high, 3 medium, 15 low
Verdict: standard_review

Findings (1)

1. [low] Comment/constant mismatch: SESSION_UUID_RE is documented as matching “lowercase hex” but the regex is case-insensitive (/i) and will match uppercase too. Evidence: /** Matches a Claude Code session UUID folder: 8-4-4-4-12 lowercase hex */ vs const SESSION_UUID_RE = /^[0-9a-f]{8}-...$/i;.

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Reviewed by inspect | Entity-level triage found 0 high-risk changes

[Palanikannan1437]

would be awesome if you could share screenshot of how this looks on your end ;)