Harden Puter stream cleanup and catalog drift

[heznpc]

Summary

• release Puter globals and best-effort close hung streaming iterators from watchdog/CHAT_ABORT paths
• suppress cancelled streaming retries/error responses and add runtime regressions for the adversarial abort races
• wire the new live course slug, refresh plugin course data, and align README/landing/store text with auth-gated AI verification and current CWS drift

Verification

• npm run lint
• npm run format:check
• npm test -- --runInBand
• npm run check:plugin && npm run check:academy && npm run check:dict-coverage && npm run check:i18n && npm run check:sync
• npm run build:bundle
• real extension Puter smoke: non-stub bundled puter.js loaded from chrome-extension://, popup observed, SkillBridge DOM present, AcademyLens not seen, no Puter ReferenceError
• npm run test:e2e

Notes

• node scripts/check-cws-drift.js --json still reports intentional live-store drift: published 1.0.1 vs local 3.5.41; landing copy now states the store listing may lag until dashboard upload.