Roadmap phased plan — moved

Consolidated into docs/PLAN.md. Most phases shipped; remainder in §3.

Roadmap — phased plan

Absorbed into the master plan. Phases 1-10 are mostly shipped (see §1); the remaining items live in §3 — primarily Phase 7 (browser perf v2, deferred post-HN), Phase 4 finishing distillation runs (gated on training), and Phase 5 MoE+distill capstone.