Adds defense-in-depth by explicitly calling activateWorker() in task_pickup.ts
after dispatchTask() returns. This ensures the worker state (active, issueId,
model, sessionKey, startTime) is properly set in projects.json even if
dispatchTask's internal state update encounters issues.
The redundant update:
- Sets active=true, issueId, and model for both spawn and reuse cases
- Sets sessionKey and startTime only on new spawns (not on session reuse)
- Provides fallback if race conditions or I/O errors affect dispatch.ts
Fixes#23
d727a812e6