CONTEXT.md documents a worker heartbeat that does not exist

[Alimedhat000]

Summary

CONTEXT.md has a "Heartbeat" section saying workers write a heartbeat to Redis so a dead worker's locks are released. No heartbeat exists in the codebase.

Evidence

• CONTEXT.md:139-145 (Heartbeat section).
• Grep for heartbeat across worker/src/, api/src/, shared/src/ finds nothing.

Also stale in CONTEXT.md

• "container memory (2GB), build timeout (15 min)" constraints are not enforced anywhere (see the health-checks/resource-limits issue).
• "Worker Pool" describes 2-3 workers; worker runs concurrency 1 — verify against the deployed reality.

Fix

Reconcile CONTEXT.md with the code: drop or rewrite the heartbeat section, and align the resource-limit claims with what the worker actually enforces.