v0.6.3

New Features

• add vercel-optimize and writing-guidelines agent skills
• persist per-engine composer preferences
• add builtin claude model catalog with override precedence
• rework context usage indicator with ai-elements style

Fixes

• remeasure mounted rows instead of wiping virtualizer size cache

Performance Improvements

• pause background polling and cut idle render storms
• eliminate O(L^2) streaming merge and keep heavy vendors lazy
• stop heavy subtrees re-rendering on every app-shell root render
• move composer state out of app-shell root and tame render storms