0.35.3: Compact Bundled Extension Labels

• Extension wiring: Each bundled extension is now declared through a thin pointer at extensions/<name>/index.js that re-exports the exact bundled entrypoint, so the Pi startup list and pi config show @llblab/pi-kit:pi-telegram instead of the full nested path. Pins, load order and package code are unchanged, and an explicit pi.extensions still suppresses conventional directory discovery, so nothing loads twice.
• Publishing and checks: package.json publishes the pointer folder, and package tests now bind every pin to one pointer, one target and the two re-export statements a pointer may hold. Skill resolution keeps its existing node_modules paths. Only the path part of a label shortens; the @llblab/pi-kit: prefix remains and changes no runtime behavior.