feat: scaffold howtos project

Collection of usage guides and cheatsheets. Includes project docs,
topic template, and directory structure.

docs/CHEATSHEET.md

@@ -0,0 +1,23 @@
+# Cheatsheet
+
+## Quick Reference
+
+| Action              | Command                              |
+|---------------------|--------------------------------------|
+| List topics         | `ls topics/`                         |
+| Read topic          | `bat topics/<name>.md`               |
+| Add topic           | `cp docs/TEMPLATE.md topics/<n>.md`  |
+| Search across all   | `grep -ri <term> topics/`            |
+
+## File Format
+
+Each topic file follows `docs/TEMPLATE.md`:
+
+```
+# <Topic>
+## Overview        — one-liner description
+## Common Commands — daily-driver commands
+## Examples        — real-world patterns
+## Gotchas         — pitfalls and edge cases
+## See Also        — related topics, links
+```