fix: improve file sharing on Android using app-private storage

- Replace direct file writing with app-private storage + share dialog
- Add Share plugin for cross-platform file sharing
- Update file paths configuration for Android
- Fix permission issues by using Directory.Data instead of Documents
- Simplify file export flow in DataExportSection

android/app/capacitor.build.gradle

@@ -12,6 +12,7 @@ dependencies {
     implementation project(':capacitor-app')
     implementation project(':capacitor-camera')
     implementation project(':capacitor-filesystem')
+    implementation project(':capacitor-share')
     implementation project(':capawesome-capacitor-file-picker')
 
 }

android/app/src/main/assets/capacitor.plugins.json

@@ -11,6 +11,10 @@
 		"pkg": "@capacitor/filesystem",
 		"classpath": "com.capacitorjs.plugins.filesystem.FilesystemPlugin"
 	},
+	{
+		"pkg": "@capacitor/share",
+		"classpath": "com.capacitorjs.plugins.share.SharePlugin"
+	},
 	{
 		"pkg": "@capawesome/capacitor-file-picker",
 		"classpath": "io.capawesome.capacitorjs.plugins.filepicker.FilePickerPlugin"

android/app/src/main/res/xml/file_paths.xml

@@ -2,4 +2,5 @@
 <paths xmlns:android="http://schemas.android.com/apk/res/android">
     <external-path name="my_images" path="." />
     <cache-path name="my_cache_images" path="." />
+    <files-path name="my_files" path="." />
 </paths>

android/capacitor.settings.gradle

@@ -11,5 +11,8 @@ project(':capacitor-camera').projectDir = new File('../node_modules/@capacitor/c
 include ':capacitor-filesystem'
 project(':capacitor-filesystem').projectDir = new File('../node_modules/@capacitor/filesystem/android')
 
+include ':capacitor-share'
+project(':capacitor-share').projectDir = new File('../node_modules/@capacitor/share/android')
+
 include ':capawesome-capacitor-file-picker'
 project(':capawesome-capacitor-file-picker').projectDir = new File('../node_modules/@capawesome/capacitor-file-picker/android')