feat(v1.8.0): IMPL_019 Homescreen Widgets Implementation

Complete Jetpack Glance Widget Framework
- Implement NoteWidget with 5 responsive size classes
- Support TEXT and CHECKLIST note types
- Material You dynamic colors integration
- Interactive checklist checkboxes in large layouts
- Read-only mode for locked widgets

Widget Configuration System
- NoteWidgetConfigActivity for placement and reconfiguration (Android 12+)
- NoteWidgetConfigScreen with note selection and settings
- Lock widget toggle to prevent accidental edits
- Background opacity slider with 0-100% range
- Auto-save on back navigation plus Save FAB

Widget State Management
- NoteWidgetState keys for per-instance persistence via DataStore
- NoteWidgetActionKeys for type-safe parameter passing
- Five top-level ActionCallback classes
  * ToggleChecklistItemAction (updates checklist and marks for sync)
  * ToggleLockAction (toggle read-only mode)
  * ShowOptionsAction (show permanent options bar)
  * RefreshAction (reload from storage)
  * OpenConfigAction (launch widget config activity)

Responsive Layout System
- SMALL (110x80dp): Title only
- NARROW_MEDIUM (110x110dp): Preview or compact checklist
- NARROW_TALL (110x250dp): Full content display
- WIDE_MEDIUM (250x110dp): Preview layout
- WIDE_TALL (250x250dp): Interactive checklist

Interactive Widget Features
- Tap content to open editor (unlock) or show options (lock)
- Checklist checkboxes with immediate state sync
- Options bar with Lock/Unlock, Refresh, Settings, Open in App buttons
- Per-widget background transparency control

Connection Leak Fixes (Part of IMPL_019)
- Override put/delete/createDirectory in SafeSardineWrapper with response.use{}
- Proper resource cleanup in exportAllNotesToMarkdown and syncMarkdownFiles
- Use modern OkHttp APIs (toMediaTypeOrNull, toRequestBody)

UI Improvements (Part of IMPL_019)
- Checkbox toggle includes KEY_LAST_UPDATED to force Glance recomposition
- Note selection in config is visual-only (separate from save)
- Config uses moveTaskToBack() plus FLAG_ACTIVITY_CLEAR_TASK
- Proper options bar with standard Material icons

Resources and Configuration
- 8 drawable icons for widget controls
- Widget metadata file (note_widget_info.xml)
- Widget preview layout for Android 12+ widget picker
- Multi-language strings (English and German)
- Glance Jetpack dependencies version 1.1.1

System Integration
- SyncWorker updates all widgets after sync completion
- NoteEditorViewModel reloads checklist state on resume
- ComposeNoteEditorActivity reflects widget edits
- WebDavSyncService maintains clean connections
- AndroidManifest declares widget receiver and config activity

Complete v1.8.0 Widget Feature Set
- Fully responsive design for phones, tablets and foldables
- Seamless Material Design 3 integration
- Production-ready error handling
- Zero connection leaks
- Immediate UI feedback for all interactions

android/app/src/main/res/values-de/strings.xml

@@ -511,4 +511,20 @@
         <item quantity="one">%d erledigt</item>
         <item quantity="other">%d erledigt</item>
     </plurals>
+
+    <!-- ============================= -->
+    <!-- WIDGETS v1.8.0                -->
+    <!-- ============================= -->
+    <string name="widget_name">Simple Notes</string>
+    <string name="widget_description">Zeige eine Notiz oder Checkliste auf dem Startbildschirm</string>
+    <string name="widget_config_title">Notiz auswählen</string>
+    <string name="widget_config_hint">Tippe auf eine Notiz, um sie als Widget hinzuzufügen</string>
+    <string name="widget_config_save">Speichern</string>
+    <string name="widget_lock_label">Widget sperren</string>
+    <string name="widget_lock_description">Versehentliches Bearbeiten verhindern</string>
+    <string name="widget_note_not_found">Notiz nicht gefunden</string>
+    <string name="widget_opacity_label">Hintergrund-Transparenz</string>
+    <string name="widget_opacity_description">Transparenz des Widget-Hintergrunds anpassen</string>
+    <string name="widget_preview_title">Einkaufsliste</string>
+    <string name="widget_preview_content">Milch, Eier, Brot, Butter, Käse, Tomaten, Nudeln, Reis, Olivenöl…</string>
 </resources>