[P0.DOC] Finalize Phase 0 Documentation & Handover

### Goal
Update docs, handover logs, and pending documentation ledger for Phase 0 completion.

### Dependencies
[P0.1], [P0.2], [P0.3], [P0.4], [P0.5], [P0.6], [P0.7]

### Acceptance Criteria
- `docs/handover/phase-0-setup-handover.md` updated
- `docs/PENDING_DOC_UPDATES.md` cleared for Phase 0

### Run
`/close-task`

Review the Phase 0 outputs from [P0.1] through [P0.7], then update docs/handover/phase-0-setup-handover.md and docs/PENDING_DOC_UPDATES.md. Done means the handover reflects Phase 0 completion, the pending documentation ledger is cleared for Phase 0, and /close-task can be run.

Written by the indexing model from the issue text.