feat(P3): IHF Phase 3 complete — Governance and Decision Linkage

Implements the full governance layer:
- Schema: requirements, decision_records, policy_references,
  implementation_change_references; requirement_candidates gets
  requirement_id back-reference
- RequirementsController (index/show; promotion-only create)
- DecisionRecordsController (CRUD + policy/impl ref management)
- GovernanceDashboardAction on HubsController (AutoRefresh)
- PromoteToRequirementAction + LinkToDecisionAction on candidates
- Outcome immutability enforced at controller level (fill excludes outcome)
- Full six-outcome vocabulary with Tailwind color roles
- Integration tests for all Phase 3 paths
- FrontController: registers Phase 2 missing controllers + all Phase 3
- SCOPE.md + docs/phase3-summary.md updated

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Web/View/Hubs/Show.hs

@@ -33,6 +33,10 @@ instance View ShowView where
                        class="text-sm border border-indigo-300 text-indigo-700 px-3 py-1.5 rounded hover:bg-indigo-50">
                         Triage Dashboard
                     </a>
+                    <a href={GovernanceDashboardAction { hubId = hub.id }}
+                       class="text-sm border border-purple-300 text-purple-700 px-3 py-1.5 rounded hover:bg-purple-50">
+                        Governance Dashboard
+                    </a>
                     <a href={EditHubAction { hubId = hub.id }}
                        class="text-sm border border-gray-300 px-3 py-1.5 rounded hover:bg-gray-50">
                         Edit