feat(maestro): add daemon tmux/sidecar/worktree primitives

Local primitives for `maestrod`, no network code yet:

- `tmux`: subprocess wrapper around new-session, kill-session,
  list-sessions (filtered to maestro-*), send-keys -l, pipe-pane -o,
  resize-window, kill-server.
- `sidecar`: atomic JSON metadata store keyed by session UUID, with
  load_all for daemon restart recovery.
- `worktree`: `git worktree add -b` with collision-proof generated paths
  and `git worktree remove --force` for cleanup_on_kill.

Integration tests use real tmux (isolated via unique socket + temp
TMUX_TMPDIR) and real git (tmpdir repo).

Closes NAP-212.

Cargo.toml

@@ -11,8 +11,11 @@ publish = false
 
 [workspace.dependencies]
 chrono = { version = "0.4", default-features = false, features = ["clock", "serde"] }
+maestro-protocol = { path = "crates/maestro-protocol" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+tempfile = "3"
+thiserror = "1"
 uuid = { version = "1", features = ["v4", "serde"] }
 
 [profile.release]