Define the long-term AI application roadmap

[fengting124]

What

• define the authoritative product boundary for a Java backend and AI application engineering portfolio
• formalize the durable review queue and anomaly-pool workflow
• split delivery into eight independently verifiable phases
• define local, Docker, server, GPU, and non-goal boundaries

Why

Earlier roadmap documents contain historical assumptions and no longer reflect the reliable dispatch, execution lease, upload security, or clarified job target. This specification becomes the durable decision baseline for future branches.

Verification

• specification self-reviewed for placeholders, scope contradictions, and unsupported capability claims
• git diff --check passed
• documentation index updated