chore(v1.8.0): IMPL_05 Version Bump - v1.7.2 → v1.8.0

- Update versionCode from 19 to 20
- Update versionName from "1.7.2" to "1.8.0"
- Create F-Droid changelog for versionCode 20 (EN + DE)
- Update CHANGELOG.md with comprehensive v1.8.0 entry (all 16 features)
- Update CHANGELOG.de.md with German v1.8.0 entry
- Add commit hashes to all changelog entries for traceability

Major feature release: Widgets with interactive checklists, note/checklist
sorting, server deletion detection, sync status legend, live sync progress,
parallel downloads, checklist UX improvements, and widget text display fix.
Complete changelog lists all features with commit references.

android/app/build.gradle.kts

@@ -20,8 +20,8 @@ android {
         applicationId = "dev.dettmer.simplenotes"
         minSdk = 24
         targetSdk = 36
-        versionCode = 19  // 🔧 v1.7.2: Critical Bugfixes (Timestamp Sync, SyncStatus, etc.)
-        versionName = "1.7.2"  // 🔧 v1.7.2: Critical Bugfixes
+        versionCode = 20  // 🎉 v1.8.0: Widgets, Sorting, UI Polish, Post-Update Changelog
+        versionName = "1.8.0"  // 🎉 v1.8.0: Major Feature Release
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }