style(no-slop): remove every em-dash + banned words across all modules + capstone

Apply the no-ai-slop standard (now binding in AGENTS.md): the em-dash character is
banned outright (restructured, not blind-replaced), plus the banned word/phrase
list (delve, leverage, robust, seamless, truly, unlock, etc.). 0 em-dashes remain
in modules + capstone; the only "robust" left is the planted M10 ai-change.patch
trap. Module H1 titles use a colon separator.

All deliberate teaching devices preserved; labs compile/parse (py/sh/yaml/json);
no junk. AGENTS.md updated with the hard no-slop rules.

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

modules/21-skills-teaching-the-ai-your-playbook/lab/tasks-app/cli.py

@@ -5,7 +5,7 @@ Run it:
     python cli.py list
     python cli.py count
 
-State is kept in tasks.json next to this file. The same minimal app from Module 1 onward — the
+State is kept in tasks.json next to this file. The same minimal app from Module 1 onward; the
 target your "add a command" skill extends.
 """