Release v1.2.0 - Local Backup & Markdown Desktop Integration

✨ New Features:
- Local backup/restore system with 3 modes (Merge/Replace/Overwrite)
- Markdown export for desktop access via WebDAV mount
- Dual-format architecture (JSON master + Markdown mirror)
- Settings UI extended with backup & desktop integration sections

📝 Changes:
- Server restore now asks for mode selection (user safety)
- WebDAV mount instructions for Windows/Mac/Linux in README
- Complete CHANGELOG.md with all version history

🔧 Technical:
- BackupManager.kt for complete backup/restore logic
- Note.toMarkdown/fromMarkdown with YAML frontmatter
- ISO8601 timestamps for desktop compatibility
- Last-Write-Wins conflict resolution

📚 Documentation:
- CHANGELOG.md (Keep a Changelog format)
- README updates (removed Joplin/Obsidian, added WebDAV-mount)
- F-Droid changelogs (DE+EN, under 500 chars)
- SYNC_ARCHITECTURE.md in project-docs
- MARKDOWN_DESKTOP_REALITY_CHECK.md strategic plan
- WEB_EDITOR_PLAN_v1.3.0.md for future web editor feature

android/app/build.gradle.kts

@@ -17,8 +17,8 @@ android {
         applicationId = "dev.dettmer.simplenotes"
         minSdk = 24
         targetSdk = 36
-        versionCode = 4  // 🔥 v1.1.2: UX Fixes + CancellationException Handling
-        versionName = "1.1.2"  // 🔥 v1.1.2: Better UX + Job Cancellation Fix
+        versionCode = 5  // 🔥 v1.2.0: Local Backup + Markdown Desktop Integration
+        versionName = "1.2.0"  // 🔥 v1.2.0: Backup/Restore + Joplin/Obsidian Support
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"