v3.3.0: File Manager, SSH/Remote access, Approval gate

- File Manager: browse device files, open/preview, install APKs
- SSH/Remote: [SSH_EXEC], [SSH_UPLOAD], [SSH_DOWNLOAD], [REMOTE_EXEC], [CURL_EXEC]
- Approval gate: all sensitive actions require user approval
- New FileManagerPlugin native plugin
- Updated agentic system prompt with external access docs
- Cleaned up stale .idsig artifacts from releases/

android/app/build.gradle

@@ -21,8 +21,8 @@ android {
         applicationId "ai.z.chat"
         minSdkVersion rootProject.ext.minSdkVersion
         targetSdkVersion rootProject.ext.targetSdkVersion
-        versionCode 23
-        versionName "3.2.0"
+        versionCode 25
+        versionName "3.3.0"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         aaptOptions {
             ignoreAssetsPattern = '!.svn:!.git:!.ds_store:!*.scc:.*:!CVS:!thumbs.db:!picasa.ini:!*~'