Power C on the C64 calls ML as sys(addr, &a, &x, &y); the bank argument
from the manual's C128 library page made sys() jump to $000F and crash.
The ML row painter now runs. Quitting resets through $FCE2 because Power C
owns BASIC's zero-page pointers. Notes and Power C skill updated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

- skills/powerc: K&R dialect limits, shell/editor, cc/link pipeline, library, ML interface
- vice-emulator skill: keybuf rules, warp, c1541 PETSCII source files, Power C workflow
- examples: powerc-ced.bat, powerc-build.bat

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>