Guide: creating and applying your own patterns

[engmung]

Write a how-to that takes someone from idea → a pattern running on their device:

• Make a pattern in the Pattern Lab (JS, live preview, knobs/buttons).
• Convert it to a firmware .h (the "Copy C++ prompt" + the conversion notes).
• Drop it into a custom slot (custom1.h …) per firmware/patternflow/README.md.
• Compile + flash (browser flasher or Arduino IDE).

Teased from the web Flash tab ("a guide ... is coming soon"). Likely lives as a
top-level PATTERN_GUIDE.md and/or a page linked from the site once written.