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/RequirementCandidates/Show.hs

@@ -67,6 +67,9 @@ instance View ShowView where
                 {renderReviewerSection candidate mAssignment users}
             </div>
 
+            <!-- Phase 3: Promote to Requirement / Link to Decision -->
+            {renderGovernanceActions candidate}
+
             <!-- Triage history -->
             <div class="bg-white rounded-lg border border-gray-200 px-6 py-4">
                 <h2 class="text-sm font-semibold text-gray-700 mb-3">Triage History</h2>
@@ -167,6 +170,51 @@ renderTriageRow ts = [hsx|
     </li>
 |]
 
+renderGovernanceActions :: RequirementCandidate -> Html
+renderGovernanceActions candidate
+    | candidate.status == "accepted" = [hsx|
+        <div class="bg-white rounded-lg border border-indigo-200 px-6 py-4">
+            <h2 class="text-sm font-semibold text-gray-700 mb-3">Governance</h2>
+            <div class="flex flex-wrap gap-3">
+                {renderPromoteButton candidate}
+                {renderLinkDecisionButton candidate}
+            </div>
+        </div>
+    |]
+    | otherwise = mempty
+
+renderPromoteButton :: RequirementCandidate -> Html
+renderPromoteButton candidate =
+    case candidate.requirementId of
+        Just rid -> [hsx|
+            <a href={ShowRequirementAction { requirementId = rid }}
+               class="text-sm text-green-700 bg-green-50 border border-green-200 px-3 py-1.5 rounded hover:bg-green-100">
+                Requirement →
+            </a>
+        |]
+        Nothing -> [hsx|
+            <form method="POST"
+                  action={PromoteToRequirementAction { requirementCandidateId = candidate.id }}>
+                {hiddenField "authenticity_token"}
+                <button type="submit"
+                        class="text-sm bg-indigo-600 text-white px-3 py-1.5 rounded hover:bg-indigo-700">
+                    Promote to Requirement
+                </button>
+            </form>
+        |]
+
+renderLinkDecisionButton :: RequirementCandidate -> Html
+renderLinkDecisionButton candidate = [hsx|
+    <form method="POST"
+          action={LinkToDecisionAction { requirementCandidateId = candidate.id }}>
+        {hiddenField "authenticity_token"}
+        <button type="submit"
+                class="text-sm bg-gray-700 text-white px-3 py-1.5 rounded hover:bg-gray-800">
+            Create Decision Record
+        </button>
+    </form>
+|]
+
 statusClass :: Text -> Text
 statusClass "open"      = "bg-blue-100 text-blue-700"
 statusClass "in_review" = "bg-yellow-100 text-yellow-800"