fix(mypy): 1/2 mypy complains about conflicting main.py modules if we…

… do not use unique names for the sample modules

ERROR:
```
samples/coffee-shop/main.py: error: Duplicate module named "main" (also at "./samples/basic-gemini/main.py")
samples/coffee-shop/main.py: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#mapping-file-paths-to-modules for more info
samples/coffee-shop/main.py: note: Common resolutions include: a) using `--exclude` to avoid checking one of them, b) adding `__init__.py` somewhere, c) using `--explicit-package-bases` or adjusting MYPYPATH
```

CHANGELOG:
- [ ] Use the same structure as other packages with unambiguous names
  for entry point modules to avoid collisions to satisfy mypy.
- [ ] Enable strict mypy checks by default; relax as necessary.

py/pyproject.toml

@@ -154,19 +154,20 @@ mypy_path = [
   "plugins/ollama/src",
   "plugins/pinecone/src",
   "plugins/vertex-ai/src",
-  "samples/basic-gemini",
-  "samples/coffee-shop",
-  "samples/context-caching",
-  "samples/flow-sample1",
-  "samples/hello",
-  "samples/menu",
-  "samples/prompt-file",
-  "samples/rag",
-  "samples/vertex-ai-model-garden",
-  "samples/vertex-ai-reranker",
-  "samples/vertex-ai-vector-search",
+  "samples/basic-gemini/src",
+  "samples/coffee-shop/src",
+  "samples/context-caching/src",
+  "samples/flow-sample1/src",
+  "samples/hello/src",
+  "samples/menu/src",
+  "samples/prompt-file/src",
+  "samples/rag/src",
+  "samples/vertex-ai-model-garden/src",
+  "samples/vertex-ai-reranker/src",
+  "samples/vertex-ai-vector-search/src",
 ]
 namespace_packages = true
+strict = true
 warn_unused_configs = true
 
 [tool.datamodel-codegen]

py/samples/basic-gemini/src/basic-gemini.py

@@ -0,0 +1,12 @@
+# Copyright 2025 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+"""A stub for the sample to come."""
+
+
+def main() -> None:
+    print('Hey')
+
+
+if __name__ == '__main__':
+    main()

py/samples/coffee-shop/src/coffee-shop.py

@@ -0,0 +1,12 @@
+# Copyright 2025 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+"""A stub for the sample to come."""
+
+
+def main() -> None:
+    print('Hey')
+
+
+if __name__ == '__main__':
+    main()

py/samples/context-caching/src/context-caching.py

@@ -0,0 +1,12 @@
+# Copyright 2025 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+"""A stub for the sample to come."""
+
+
+def main() -> None:
+    print('Hey')
+
+
+if __name__ == '__main__':
+    main()

py/samples/flow-sample1/src/flow-sample1.py

@@ -0,0 +1,12 @@
+# Copyright 2025 Google LLC
+# SPDX-License-Identifier: Apache-2.0
+
+"""A stub for the sample to come."""
+
+
+def main() -> None:
+    print('Hey')
+
+
+if __name__ == '__main__':
+    main()