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/06-branches-sandboxes-for-experiments/README.md

@@ -263,7 +263,7 @@ deliberately create and resolve a merge conflict — using the AI to help resolv
 1. Confirm you're on `main` and clean, then create an experiment branch and switch to it:
 
    ```bash
-   cd ~/workflow-course/tasks-app
+   cd ~/ai-workflow-course/tasks-app
    git switch main
    git status                       # must be clean
    git switch -c experiment/priorities