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/08-remotes-and-hosting/lab/verify-backup.sh

@@ -1,13 +1,13 @@
 #!/usr/bin/env bash
 #
-# verify-backup.sh — prove that your remote is a real, complete offsite backup.
+# verify-backup.sh: prove that your remote is a real, complete offsite backup.
 #
 # Module 8 lab helper. Run it from inside your tasks-app repo:
 #     bash verify-backup.sh
 #
 # It checks three things, the three that make "I pushed" actually mean "it's backed up":
 #   1. A remote is configured at all.
-#   2. Your current branch is fully pushed — no commits stranded only on this disk.
+#   2. Your current branch is fully pushed; no commits stranded only on this disk.
 #   3. A fresh clone of the remote carries the EXACT SAME commit count as your local repo,
 #      i.e. the offsite copy is the whole history, not a snapshot.
 #
@@ -64,7 +64,7 @@ if [ -z "$upstream" ]; then
 else
   ahead="$(git rev-list --count "${upstream}..HEAD" 2>/dev/null || echo "?")"
   if [ "$ahead" = "0" ]; then
-    pass "Branch '$branch' is fully pushed to $upstream — nothing stranded on this disk."
+    pass "Branch '$branch' is fully pushed to $upstream, nothing stranded on this disk."
   else
     fail "Branch '$branch' is $ahead commit(s) ahead of $upstream. Run: git push"
     status=1
@@ -85,7 +85,7 @@ if git clone --quiet "$remote_url" "$tmp/clone" 2>/dev/null; then
   fi
 
   if [ "$clone_count" = "$local_count" ]; then
-    pass "Fresh clone has $clone_count commit(s) — identical to your local $local_count."
+    pass "Fresh clone has $clone_count commit(s), identical to your local $local_count."
     printf "\n%sThe offsite copy is COMPLETE: every commit, not just the latest files.%s\n" "$GREEN$BOLD" "$RESET"
     printf "That is the backup half of the course's backup-and-recovery thread.\n"
   else