Apply planning candidates to live Fabric issue state

[briansrls]

Accepting a planning candidate updates live editorial state in Fabric. The editor supports typed field changes, independent parent/blocker relations and draft children; dashboard and worker inputs derive from accepted state.

Proposals are immutable. Acceptance requires the accountable authenticated human and CSRF, validates the resulting graph, and commits children, assignments, parent changes and the operation receipt with one head CAS. Stable retries recover the original result. Executable bindings and source completion/supersession authority remain independent of editorial text.

The integrated serve blocker is fixed. Clean code commit 827cb0e6afc59c07b99cb04c24f710655d666d7b, using its own freshly built binary, compiled all 1,049 modules and reached readiness for roadmap_serve_handle_srv2_preview on an OS-selected loopback port. The check then stopped the process without sending HTTP requests. The subsequent commit contains only documentation and receipts. Reproduce with python3 tools/tests/roadmap_serve_readiness_control.py (26 GiB ceiling).

The full gate exposed and now covers missing row/response fields, the missing planning-event renderer, stale sandbox/issue calls, generic request-construction errors, and the legacy broker request boundary. The broker adapter preserves transport observation for its existing trust/capability/writer policy; it does not convert Google/service authentication into tailnet identity or implement A7.

Validation: 40 planning controls and two adapter controls pass with the branch-built binary; earlier browser and independent-process acceptance race controls also pass. Build/readiness receipts and rerunnable controls are included under docs/receipts/planning-candidate-fabric/. The prior 6 GiB attempts were inconclusive and the focused controls alone did not establish integrated readiness.

This remains a draft stacked on #12465 (codex/allocation-demo), whose HOLD is unchanged. Protected session/storage commissioning and live post-acceptance refresh remain runtime gates. No preview unit, live dashboard, DNS, deployment or merge was changed. The separate Ask Fabric planning-worker dispatch workflow is outside this change.

See docs/plans/planning-candidate-fabric.md and docs/receipts/planning-candidate-fabric/editor-validation.md for details. The formatting-only commit normalizes inherited Rust whitespace required by the repository hook.