Add docs/VISION.md (product themes, v1.0 bar, agent slice hints) and
README maps under docs/ and agent/. Point ROADMAP, BACKLOG, LOOP,
CLAUDE, HARDWARE, and the root README at the split: VISION = intent,
BACKLOG = executable queue, ROADMAP = design history, .claude = harness
only. Mark v1.0 track in BACKLOG PROPOSED for human triage.
