refactor: deepen modules across rust core + react widget

CHANGELOG.md

@@ -17,3 +17,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - Widget CRUD: new focus, delete focus, add and remove tasks.
 - `settings.yaml` with focus and task caps; cap badge and macOS overload notifications.
 - Edit-proposal modal, empty-state hero, and v1 README.
+
+### Changed
+
+- Cap notifications now flow through a `CapNotifier` trait owned by the commands crate; the Tauri shell provides a single adapter, removing the inline cap-evaluation/notification logic from the app composition root.
+- Proposal accept/reject now lives in a dedicated `ProposalLifecycle` module that owns proposal load → edit → validate → mutate → record-decision → clear-queue. The `ProposalDispatcher`/`*Applier` strategy traits are removed; the inline `match` over `ProposalKind` replaces the per-kind adapters. Focus creation in the direct path and the proposal path now share a single helper.
+- Tauri filesystem watchers now share a single `install_change_handlers` helper that fans a debounced change event out to a list of handlers, replacing the asymmetric mix of inline closure and per-watcher helper.
+- React widget composes its three async data sources through a single `useAppState` hook with one readiness contract; proposal-reader errors now surface in the UI instead of being silently swallowed.