Phase 9E.2: extract AI job controller

[FernandoAbishai]

Summary

• extract AI active-job state and start/poll/cancel/retry transport into a vertical controller
• preserve PR Fix AI job lifecycle safety #77 single-flight, workspace/run identity, cancel-busy, and fail-closed polling behavior
• keep providers, request payload construction, notices, typed result application, and publishing fingerprint/JIT logic in AIPanel

Validation

• all frontend test:* scripts
• npm run smoke:golden-creator-path
• npm run lint
• npm run build:frontend
• git diff --check

Two independent exact-current blocker/HIGH reviews: 0 / 0.

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