feat: implement cloud upload with WebDAV and SFTP support

- Add CloudUploadService with WebDAV and SFTP upload methods
- Add UploadQueueProvider for managing upload queue
- Integrate upload trigger after download completes
- Update CloudSettingsPage with actual connection test and queue UI
- Add webdav_client ^1.2.2 and dartssh2 ^2.13.0 dependencies
- Remove Google Drive option (not implemented)
- Bump version to 3.4.0+72

pubspec.lock

@@ -41,6 +41,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.7.0"
+  asn1lib:
+    dependency: transitive
+    description:
+      name: asn1lib
+      sha256: "9a8f69025044eb466b9b60ef3bc3ac99b4dc6c158ae9c56d25eeccf5bc56d024"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.6.5"
   async:
     dependency: transitive
     description:
@@ -249,6 +257,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.1.3"
+  dartssh2:
+    dependency: "direct main"
+    description:
+      name: dartssh2
+      sha256: bb242396c1d90f05c261b5eb8338cc67167e803c0948b0207029339cc568a66c
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.13.0"
   dbus:
     dependency: transitive
     description:
@@ -821,6 +837,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "7.0.1"
+  pinenacl:
+    dependency: transitive
+    description:
+      name: pinenacl
+      sha256: "57e907beaacbc3c024a098910b6240758e899674de07d6949a67b52fd984cbdf"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.6.0"
   platform:
     dependency: transitive
     description:
@@ -837,6 +861,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  pointycastle:
+    dependency: transitive
+    description:
+      name: pointycastle
+      sha256: "4be0097fcf3fd3e8449e53730c631200ebc7b88016acecab2b0da2f0149222fe"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.9.1"
   pool:
     dependency: transitive
     description:
@@ -1346,6 +1378,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.3"
+  webdav_client:
+    dependency: "direct main"
+    description:
+      name: webdav_client
+      sha256: "682fffc50b61dc0e8f46717171db03bf9caaa17347be41c0c91e297553bf86b2"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.2"
   webkit_inspection_protocol:
     dependency: transitive
     description: