Add notification history panel with tabbed bottom panel

[an0nn30]

Summary

Adds a tabbed bottom panel with a built-in Notifications history tab that logs all toast notifications from the current session. Plugins that register bottom panels get their own tabs alongside it.

• Every toast (in-app and native) is recorded in an in-memory history array
• Bottom panel header becomes a tab bar: [Notifications] [Plugin A] [Plugin B]
• Notification entries show timestamp, colored level dot, title, and body
• Clear button empties the history
• Live updates: new notifications appear immediately when the panel is open
• History resets on app restart (in-memory only, no disk persistence)
• Bottom panel visibility persisted in state.toml across sessions
• Plugin bottom panels routed to the tab system via existing panel registration

Changes

File	What
frontend/toast.js	getHistory(), onNotification(), clearHistory() API
frontend/notification-panel.js	New module: tab management, history renderer, plugin tab API
frontend/index.html	Bottom panel HTML/CSS restructured for tabs, notification entry styles, init + persistence wiring
frontend/plugin-widgets.js	Route bottom-panel plugins to notification panel tabs
src/lib.rs	bottom_panel_visible in SavedLayout/WindowLayout

Test plan

• cargo test --workspace — 346 tests pass
• Toggle bottom panel (Cmd+Shift+J) — Notifications tab visible
• Trigger toasts — entries appear with timestamp, level dot, title/body
• Click Clear — history empties
• Close/reopen panel — history preserved within session
• Restart app — history is empty
• Panel visibility persists across sessions

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid dropping bottom-panel widget updates prematurely

This early return diverts plugin-widgets-updated events away from the legacy [data-plugin-handle] container path, but frontend/index.html still creates those sidebar containers for every plugin-panel-registered event and does an initial request_plugin_render there. For bottom panels, that leaves a duplicated sidebar copy that never refreshes after the first render while the tab view keeps updating, which produces inconsistent UI state. Either stop creating sidebar containers for location === 'bottom' or keep updating them until that registration path is migrated.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Use an emitted event for plugin-tab removal

The tab cleanup listener is wired to plugin-panel-removed, but there is no emitter for that event in the current backend paths (I checked crates/conch_tauri/src/plugins/tauri_host_api.rs, which only emits plugin-panel-registered and plugin-widgets-updated). Because this callback never runs, disabling/unloading a plugin leaves stale bottom-panel tabs in the UI for the rest of the session.

Useful? React with 👍 / 👎.