move test-models from cli to integration tests

- removes test-models command to reduce binary size
- adds integration_test.go with build tag (go test -tags=integration)
- tests all provider/model combinations with language/keywords variations
- adds testdata/sample.wav for deterministic testing
- updates e2e.yml workflow to use go test instead of cli
- uses go-version-file in all workflows for consistency

.github/workflows/release.yml

@@ -27,7 +27,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.24"
+          go-version-file: go.mod
 
       - name: Install dependencies
         run: |