feat(notifications): add notification history panel and overlay UX fixes

- New toggleNotificationHistory (Ctrl+N) session-scoped history panel; slides in from same edge as notification stack
- Overlay error/recovery toast follows notifications.overlayPosition; stack and history side seeded at startup
- Cold managed background startup initializes tray and visible overlay shell before tokenization warmups finish
- Add Update button to overlay update-available notifications
- Fix Ctrl+S sentence-card flow: only Anki progress notification, no duplicate status toast
- Fix overlay notification close/actions clickability above subtitle bars on Linux
- Increase pause-until-ready default timeout from 15s to 30s

launcher/config-domain-parsers.test.ts

@@ -196,6 +196,7 @@ test('buildPluginRuntimeScriptOptParts emits config values that override plugin
       'subminer-auto_start=yes',
       'subminer-auto_start_visible_overlay=no',
       'subminer-auto_start_pause_until_ready=yes',
+      'subminer-auto_start_pause_until_ready_timeout_seconds=30',
       'subminer-osd_messages=yes',
       'subminer-texthooker_enabled=no',
     ],
@@ -224,6 +225,7 @@ test('buildPluginRuntimeScriptOptParts strips script-option delimiters from stri
       'subminer-auto_start=yes',
       'subminer-auto_start_visible_overlay=no',
       'subminer-auto_start_pause_until_ready=yes',
+      'subminer-auto_start_pause_until_ready_timeout_seconds=30',
       'subminer-osd_messages=no',
       'subminer-texthooker_enabled=no',
     ],