De-slop: remove every em-dash + banned words across all modules + capstone (#94)

Co-authored-by: claude <claude@jpaul.io>
Co-committed-by: claude <claude@jpaul.io>

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.