fix(labs): update learner working-dir path to ~/ai-workflow-course after repo rename

The repo was renamed to ai-workflow-course, so the course's working-directory
convention should match. Replace ~/workflow-course (and /home/you/...,
/ABSOLUTE/PATH/TO/...) with ~/ai-workflow-course throughout modules/ and capstone/
(20 files, incl. the MCP config example). Safe replacement — already-correct
ai-workflow-course references are untouched.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TfzV5QvtPDz8LJS3Pu5VLT

modules/22-securing-third-party-mcp-and-skills/README.md

@@ -252,7 +252,7 @@ normal question) and the attacker (you plant content the agent reads).
    a real-looking task with an injection underneath:
 
    ```bash
-   cd ~/workflow-course/tasks-app
+   cd ~/ai-workflow-course/tasks-app
    python cli.py add "$(cat /path/to/lab/poisoned-task.txt)"
    python cli.py list
    ```