AndPictures 1.0: NAS photo sync + built-in file browser

Native Kotlin Android app (single Activity + WorkManager worker) that copies
photos newer than a stored cursor to //192.168.123.2/photo/Home as
decade/year/month, deduping by filename and NAS file size.

- SMB2/3 via smbj; transparently reconnects when the server drops an idle
  session (previously surfaced as "DiskShare has already been closed")
- MediaStore cursor store, incremental uploads, size-aware dedupe
- "Phone files" / "NAS files" browser: grid, thumbnails, full-screen preview
- Release signing read from keystore.properties (never committed)

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.4-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists