Mod/cor 4 context engine

[SaketMunda]

Module

Brief: roadmap/modules/<ID>-*.md

What changed

Definition of Done

• Every item in the brief's Acceptance criteria is met and demonstrated (test or recorded manual check).
• scripts/verify.sh is green (typecheck, lint, unit tests).
• New logic in packages/* has unit tests (target ≥80% line coverage on new files). UI logic (state, reducers, parsers) is tested. Pure presentation isn't required to be.
• No any / as unknown as at package boundaries. Every external input is validated with zod.
• No new network destinations except ones the user configured. No telemetry.
• Errors are handled: user-facing failures show an actionable message, and nothing fails silently.
• Brief updated: Status, Handoff notes (what was built, deviations, known gaps, follow-ups).
• PR opened from mod/<ID>-<slug>, description links the brief, CI green.

Acceptance criteria evidence

#	Criterion	Evidence