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/23-working-with-existing-codebases/lab/skills/map-this-repo.md

@@ -2,7 +2,7 @@
 
 A navigation playbook (a Module 21 skill) for orienting in a codebase you didn't write.
 Point Claude Code (or sub your own agent) at this file as a skill, or paste it in as instructions. The goal is a
-**read-only** mental model — no edits happen here.
+**read-only** mental model; no edits happen here.
 
 ## When to use
 At the start of any session on an unfamiliar repo, before any change is discussed.
@@ -19,7 +19,7 @@ At the start of any session on an unfamiliar repo, before any change is discusse
    `ARCHITECTURE`, or committed AI-instructions file. Treat these as claims to verify, not truth.
 2. Identify the **entry points**: how does this thing start? (CLI `main`, web server, library
    exports.) Name the exact file(s).
-3. Trace **one representative request/command end to end** — from entry point to where it does its
+3. Trace **one representative request/command end to end**, from entry point to where it does its
    real work and back. List the files it passes through, in order.
 4. Produce an **architecture summary** (max ~1 page):
    - One paragraph: what this project does and how it's structured.