chore(repo): improve contributor experience

.github/workflows/ci.yml

@@ -37,6 +37,7 @@ jobs:
               - 'pubspec.lock'
               - 'analysis_options.yaml'
               - 'l10n.yaml'
+              - '.fvmrc'
               - '.github/workflows/ci.yml'
             go:
               - 'go_backend/**'
@@ -51,6 +52,7 @@ jobs:
               - 'lib/services/platform_bridge.dart'
               - 'pubspec.yaml'
               - 'pubspec.lock'
+              - '.fvmrc'
               - '.github/workflows/ci.yml'
 
   flutter:
@@ -67,6 +69,7 @@ jobs:
         uses: subosito/flutter-action@v2
         with:
           channel: "stable"
+          flutter-version-file: .fvmrc
           cache: true
 
       - name: Cache pub dependencies
@@ -102,8 +105,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v6
         with:
-          # Keep in sync with release.yml
-          go-version: "1.26.5"
+          go-version-file: go_backend/go.mod
           cache-dependency-path: go_backend/go.sum
 
       - name: Check formatting
@@ -134,13 +136,14 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v6
         with:
-          go-version: "1.26.5"
+          go-version-file: go_backend/go.mod
           cache-dependency-path: go_backend/go.sum
 
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with:
           channel: "stable"
+          flutter-version-file: .fvmrc
           cache: true
 
       - name: Setup Gradle