Use FVM in GitHub Actions and migrate to Flutter 3.32.4 (#641)

* feat: implement Flutter version management using FVM across CI workflows

* Flutter 3.29.3 + minor Package upgrades

* Replace deprecated `withOpacity`

* Upgrade major package versions without breaking changes.

* Disable unnecessary_async rule

Re-enable later

* New language version and automated fixes

- unnecessary_breaks
- unnecessary_underscore

* Update BUILDING.md to use fvm commands

* Add gitignore files for Android and iOS build artifacts

* Migrate iOS dependencies to Swift Package Manager

This is being done automatically by Flutter

* Flutter 3.32.4

* New sdk version

* docs: add IDE setup instructions and troubleshooting guide for FVM integration

.github/workflows/ci.yaml

@@ -29,19 +29,32 @@ jobs:
         uses: actions/checkout@v3
         with:
           submodules: recursive
+
       - name: Setup Java
         uses: actions/setup-java@v3
         with:
           distribution: 'temurin'
           java-version: '11'
-      - name: Setup Flutter 
-        uses: subosito/flutter-action@v2
+
+      - name: Setup Flutter and FVM
+        id: fvm-config-action
+        uses: kuhnroyal/flutter-fvm-config-action@v2
+
+      - uses: subosito/flutter-action@v2
         with:
-          flutter-version: '3.32.2'
+          flutter-version: ${{ steps.fvm-config-action.outputs.FLUTTER_VERSION }}
+          channel: ${{ steps.fvm-config-action.outputs.FLUTTER_CHANNEL }}
+          cache: true
+          cache-key: "flutter-:os:-:channel:-:version:-:arch:-:hash:"
+          cache-path: "${{ runner.tool_cache }}/flutter/:channel:-:version:-:arch:"
+          pub-cache-key: "flutter-pub:os:-:channel:-:version:-:arch:-:hash:"
+          pub-cache-path: "${{ runner.tool_cache }}/flutter/:channel:-:version:-:arch:"
+
       - name: Collect Translation Files
         run: |
           cd lib/l10n
           python3 collect_translations.py
+
       - name: Static Analysis Tests
         run: |
           python3 find_dart_files.py
@@ -52,6 +65,7 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: 3.9
+
       - name: Start InvenTree Server
         run: |
           sudo apt-get install python3-dev python3-pip python3-venv python3-wheel g++
@@ -64,6 +78,7 @@ jobs:
           invoke dev.server -a 127.0.0.1:8000 &
           invoke wait
           sleep 30
+
       - name: Unit Tests
         run: |
           flutter test --coverage