warden 0.4.0

Features

• Window menu — a new Window submenu lists every configured window: open ones carry a checkmark and raise on select; closed ones show (closed) and reopen on select (restoring persisted size/position, tabs cold). ⌘⇧T reopens the most-recently-closed window. The menu rebuilds on any window-set change (open/close/reopen).
• Global density setting — "comfortable" (default) or "compact", a proportional ~0.85× scale of the whole chrome type + spacing hierarchy. Hot-reloads live without a relaunch; mirrors curator's density mechanism.
• notify_debug config flag — traces the notification path to /tmp/warden-notify-dbg.log for diagnosing missing banners (see docs/notifications.md).

Fixes & changes

• Probe: canonical command is now amux --probe — delegates the agent/frame socket layout to amux instead of hand-inlining tmux has-session legs that drift silently. The probe also lights for a lingering amux frame (agent exited, frame still up); the example kill reaps the whole frame.
• Tab-bar treatment converged with curator — row/header type scale, a larger leading window title, and status dots bumped to match the tab scale.
• Rust toolchain pinned to 1.96.0 (rust-toolchain.toml) so formatting and lints are identical across the config-core-sharing repos.

Docs

• New docs/notifications.md — full write-up of the macOS-26 notification path and the OS-side banner regression.