Remove Omni/Agent/Worker.hs

Summary

Remove Omni/Agent/Worker.hs - the Jr worker that claims and processes tasks. This is dead code now that Telegram bot (Ava) is the main agent interface.

What It Does Currently

• start function that claims a task and runs the agent on it
• Used by jr work command (being removed in t-310)
• Contains buildFullPrompt, selectModel, selectCostByComplexity

Steps

1. Check for any imports of Omni.Agent.Worker in the codebase 2. Verify nothing else uses this module 3. Remove Omni/Agent/Worker.hs 4. Remove any related imports from other modules

Possible Blockers

If something still imports Worker.hs, evaluate whether that code is also dead or needs migration.

Acceptance Criteria

• [ ] No imports of Omni.Agent.Worker remain
• [ ] Omni/Agent/Worker.hs deleted
• [ ] Build still succeeds