0004. Hooks, harness listing, git and forge are reconciled into one model

Context

No single source knows everything:

Hooks give rich, immediate events, but only for sessions started with volee’s settings.
claude agents --json --all lists every Claude Code session on the machine with a coarse state, and is documented as the supported way to read it.
Git knows worktrees, branches, commits and push state.
The forge knows pull requests and checks.

Claude Code also keeps internal files (~/.claude/jobs, ~/.claude/sessions, transcripts) whose format is explicitly not a stable interface.

Each source is authoritative for one kind of fact (see the architecture overview). Conflicts are resolved by that rule, not by recency.
Hooks are injected per agent with claude --settings <file>. volee never edits the user’s ~/.claude/settings.json; hooks passed this way are added to the user’s own hooks.
claude agents --json --all is polled (every few seconds while a client is connected, slower otherwise) and reconciled by session id.
volee does not parse Claude Code internal files. Transcript paths received in hook payloads may be shown, never parsed for state.
Git and forge queries are triggered by events (an edit, a commit, a push seen in a hook) and by a slow timer.

Agents volee did not launch are visible with a coarse state; agents it launched get the fine-grained one.
volee keeps working when Claude Code changes its internal files.
Polling claude agents costs a process start every few seconds while the TUI is open; this is acceptable and configurable.

Parse ~/.claude/sessions/*.json and transcripts. Cheaper and richer, but undocumented and unstable.
Global hooks in the user’s settings. Would see every session in detail, but edits a file the user owns and affects every session they start.