style(no-slop): de-em-dash the internal docs + config (repo now fully clean)

- AGENTS.md (the standard-bearer), _TEMPLATE.md, handoff.md, tools/README.md:
  em-dashes removed by restructuring, banned words replaced; all policy/structure
  and decisions preserved.
- .gitea/.github sync-wiki workflows, .claude/gitea-ship.json, .gitignore: em-dashes
  in comments/log strings/notes removed; YAML/JSON still valid.

The entire tracked repo is now em-dash-free (the lone remaining `—` is inside a
regex character class in tools/build_wiki.py, intentional, matches old titles).

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

.github/workflows/sync-wiki.yml

@@ -1,9 +1,9 @@
 # Render the course (single source of truth = modules/) into the GitHub wiki on
-# every push to main. The wiki is generated BUILD OUTPUT — never hand-edit it.
+# every push to main. The wiki is generated BUILD OUTPUT; never hand-edit it.
 # This activates on the GitHub mirror; the Gitea copy uses .gitea/workflows/.
 #
 # Prerequisites (one-time on the mirror):
-#   1. The wiki must be INITIALIZED first — create any page once in the GitHub UI,
+#   1. The wiki must be INITIALIZED first; create any page once in the GitHub UI,
 #      otherwise the <repo>.wiki.git remote does not exist and the clone fails.
 #   2. A repo secret WIKI_TOKEN holds a PAT with wiki/repo write. The default
 #      GITHUB_TOKEN CANNOT push to the wiki repo, so a PAT is required.
@@ -34,7 +34,7 @@ jobs:
         run: |
           set -euo pipefail
           if [ -z "${WIKI_TOKEN:-}" ]; then
-            echo "::error::WIKI_TOKEN secret is not set — see this workflow's header."
+            echo "::error::WIKI_TOKEN secret is not set; see this workflow's header."
             exit 1
           fi
           repo="${GITHUB_REPOSITORY}"   # owner/repo