docs: propose Kubernetes pod outcome classifier

[bholmesdev]

Summary

• Adds a TECH.md spec reviewing the past week's Kubernetes backend architecture changes.
• Proposes extracting Kubernetes pod outcome classification into an explicit internal boundary.
• Documents validation, risks, and why immediate implementation should remain sequential rather than delegated.

Validation

• go test ./internal/worker

Conversation: https://staging.warp.dev/conversation/f13f266f-95ee-472d-aac3-43028bcf259f
Run: https://oz.staging.warp.dev/runs/019febc2-50bf-7510-8a24-916d50a79077

Co-Authored-By: Warp Agent agent@warp.dev

This PR was generated with Oz.