scaffold-exercises

# Scaffold Exercises Create `exercises/` structure that passes `pnpm ai-hero-cli internal lint`, then commit. ## Naming - Sections: `XX-section-name/` - Exercises: `XX.YY-exercise-name/` - dash-case names. ## Variants Each exercise needs at least one: `problem/`, `solution/`, `explainer/`. Default stub: `explainer/`. Each variant needs non-empty `readme.md`. Code variants also need `main.ts` >1 line. ## Workflow 1. Parse plan -> sections, exercises, variant types. 2. `mkdir -p` dirs. 3. Create stub readmes with title + sentence. 4. Run `pnpm ai-hero-cli internal lint`. 5. Fix until green. ## Moving Use `git mv`, update numeric prefixes, rerun lint. No `.gitkeep`, `speaker-notes.md`, broken links, or `pnpm run exercise` in readmes.