style: add ascii header, tighten verbose prose, apply style guide

[BryanChasko]

violations found during sprint-1 style audit:

• missing ascii art header
• verbose prose in opening description (run-on sentences)
• Contributing Principles section has nested bullets

reference: https://github.com/BryanChasko/heraldstack-mcp/blob/main/STYLE_GUIDE.md

kerouac brief

add ascii art header. cut opening description to 1-2 clean sentences -- strip the run-ons and parentheticals. flatten Contributing Principles to top-level bullets only. verify no banned words.

assignee: kerouac (ghost-kerouac-research-analyst via haunting)