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/12-revert-reset-and-recovery/lab/bad-clear-snippet.py

@@ -1,9 +1,9 @@
-# Module 12 lab — the deliberately BROKEN `clear` command.
+# Module 12 lab: the deliberately BROKEN `clear` command.
 #
 # Paste the elif block below into cli.py's main(), alongside the other
 # `elif command == "..."` branches (e.g. right after the "done" branch).
 # Do NOT paste this header or the import line into cli.py if json is already
-# imported there (it is) — just the elif block.
+# imported there (it is); just the elif block.
 #
 # Why it's broken: it "works" once (prints a friendly message), but it writes
 # the state file in the WRONG SHAPE. The next time the app loads tasks.json,