Fix stale sample and test wiring

Four unrelated papercuts:

- Add the llm-stream dependency group. workflow_streams/README.md tells readers
  to run `uv sync --group llm-stream` for scenario 5, but the group was never
  created, so the command fails. The sample's openai import resolves today only
  because the langfuse-tracing and langsmith-tracing groups happen to install
  openai.

- Rename tests/activity_sticky_queues to tests/worker_specific_task_queues, and
  drop the stale prefix from the two test filenames. The sample was renamed but
  its test directory was not, so the tests sat under a directory naming a sample
  that no longer exists.

- Locate google_genai's echo MCP server through the installed package rather than
  Path(__file__).parents[2], which hardcodes the distance from the test file to
  the sample and silently resolves to a nonexistent path if either moves. A
  missing server script makes the test hang rather than fail, since the client
  waits on a subprocess that never started.

- Add __init__.py to the five test directories that lacked it. Test filenames
  collide across samples by design (workflow_test.py, activity_test.py and
  mcp_test.py each appear in several), and package markers are what keep pytest
  from treating them as the same module. The five worked only because they had
  not collided yet.

Full suite unchanged at 150 collected, 148 passed, 4 skipped; mypy clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: brianstrauch

pyproject.toml

@@ -74,6 +74,7 @@ langgraph = [
     "temporalio[langgraph,langsmith]>=1.31.0",
 ]
 litellm = ["litellm>=1.85.0,<2"]
+llm-stream = ["openai>=1.4.0"]
 nexus = ["nexus-rpc>=1.1.0,<2"]
 open-telemetry = [
     "temporalio[opentelemetry]",

tests/google_genai/mcp_test.py

@@ -17,11 +17,10 @@
 )
 from temporalio.worker import Worker
 
+import google_genai.mcp as google_genai_mcp
 from google_genai.mcp.workflow import McpWorkflow
 
-ECHO_SERVER = str(
-    Path(__file__).parents[2] / "google_genai" / "mcp" / "echo_mcp_server.py"
-)
+ECHO_SERVER = str(Path(google_genai_mcp.__file__).parent / "echo_mcp_server.py")
 
 
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