fix(M1-6): apply AI-drives-git reframe, lesson=theory, de-slop, + issue fixes

Phase 1 of the reframe. M1-3 stay manual-by-hand (browser chat); M4 is the pivot
to the AI agent (Claude Code as example); M5-6 are agent-driven.

- M1: de-slop (em-dashes), relocate the build-note out of the lab. Seam devices kept.
- M2: #78 tell learner how to paste cli.py into chat; #79 commit the delete so the
  tree ends clean. restore/cold-session devices kept.
- M3: #80 define ADR; #81 create-file-before-add; #82 ls before/after merge to prove
  branch isolation; #83 drop "prose"; M3 now owns the branch-basics intro.
- M4: #84 Claude Code as the worked example; #85 AI drives git (arithmetic->calculator);
  #86 /path/to -> ~/ai-workflow-course; #87 agent does the revert+verify.
- M5: #88 ask the agent which config files to commit, then let it stage/commit
  (CLAUDE.md example; repo still uses AGENTS.md).
- M6: #90 stop re-teaching branch basics; rescope to the AI experimenting on a branch;
  the engineered conflict is now AI-resolved, learner-verified.

Closes #78
Closes #79
Closes #80
Closes #81
Closes #82
Closes #84
Closes #85
Closes #87
Closes #88
Closes #90

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

modules/04-getting-the-ai-out-of-the-browser/lab/verify.sh

@@ -8,7 +8,7 @@
 # care HOW the AI implemented it, only that `delete` works end to end.
 #
 # Copy this into your tasks-app project directory, then run it from there:
-#     cp /path/to/modules/04-getting-the-ai-out-of-the-browser/lab/verify.sh .
+#     cp ~/ai-workflow-course/modules/04-getting-the-ai-out-of-the-browser/lab/verify.sh .
 #     bash verify.sh
 #
 # (It self-locates cli.py, so it also still works if you run it in place as `bash lab/verify.sh`.)