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/03-version-control-for-words/README.md

@@ -212,7 +212,7 @@ zero.
 1. Confirm you're starting clean, then create a branch for the ADR:
 
    ```bash
-   cd ~/workflow-course/tasks-app
+   cd ~/ai-workflow-course/tasks-app
    git status                       # want: "working tree clean"
    git switch -c docs/adr-storage   # new branch, named for what it's for
    git branch                       # the * shows you're on docs/adr-storage now