fix(ci): restore pub get before dart format to fix language version detection

Without flutter pub get, .dart_tool/package_config.json does not exist
in the Dagger container. dart format then defaults to the current SDK
version (3.11+) rather than the package's declared language version
(3.3), applying tall-style formatting and failing on 90 files.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ci/main.go

@@ -71,7 +71,10 @@ func (m *Ci) CheckLayers(ctx context.Context, source *dagger.Directory) (string,
 
 // Run dart format check
 func (m *Ci) Format(ctx context.Context, source *dagger.Directory) (string, error) {
+	// pub get is required so .dart_tool/package_config.json exists; without it dart format
+	// ignores the package's language version (3.3) and applies tall-style formatting.
 	return m.Base(source).
+		WithExec([]string{"flutter", "pub", "get"}).
 		WithExec([]string{"dart", "format", "--output=none", "--set-exit-if-changed", "lib", "test"}).
 		Stdout(ctx)
 }