Fix F-Droid bot feedback issues [skip ci]

- Move fastlane metadata to repository root (was in android/fastlane)
- Add distributionSha256Sum to gradle-wrapper.properties for security
- Update Gradle Wrapper JAR to match version 8.13
- Document NonFreeNet anti-feature (HTTP support for local WebDAV servers)

Addresses F-Droid RFP issue #3458 bot feedback

fastlane/metadata/android/en-US/full_description.txt

@@ -0,0 +1,37 @@
+Simple Notes Sync is a minimalist note-taking app with WebDAV synchronization.
+
+KEY FEATURES:
+
+• Create and edit simple notes
+• WebDAV synchronization with your own server
+• Automatic synchronization on home WiFi
+• Configurable sync interval (15/30/60 minutes)
+• Transparent battery usage display
+• Material Design 3 with Dynamic Colors (Android 12+)
+• Swipe-to-delete with confirmation dialog
+• Server backup & restore
+• Fully usable offline
+• No ads, no trackers
+
+PRIVACY:
+
+Your data stays with you! The app only communicates with your own WebDAV server. No cloud services, no tracking libraries, no analytics tools.
+
+SYNCHRONIZATION:
+
+• Supports all WebDAV servers (Nextcloud, ownCloud, etc.)
+• Configurable interval: 15, 30, or 60 minutes
+• Measured battery consumption: only ~0.4% per day (at 30min)
+• Doze Mode optimized for reliable background syncs
+• Manual synchronization available anytime
+• Conflict-free merging through timestamps
+
+MATERIAL DESIGN 3:
+
+• Modern user interface
+• Dynamic Colors (Material You) on Android 12+
+• Dark Mode support
+• Intuitive gestures (Swipe-to-delete)
+
+Open Source under MIT License
+Source code: https://github.com/inventory69/simple-notes-sync