feat(P4): IHF Phase 4 complete — Outcome Observation and Antifragility Loop

Closes the IHF improvement loop. Full antifragility chain now traversable:
Widget → Annotation → Candidate → Requirement → Decision → Deployment → OutcomeSignal

New artifacts:
- DeploymentRecord (immutable, links DecisionRecord to a deployed version)
- OutcomeSignal (append-only; DB trigger prevents UPDATE/DELETE)
- ChangeEvaluation (one-per-deployment; UNIQUE constraint; 1–5 score)

New capabilities:
- DeploymentRecordsController (index, show, new, create)
- RecordOutcomeSignalAction — capture improved/regressed/neutral/inconclusive signals
- Pre/post comparison panel on deployment show (±30-day event/annotation counts)
- Regression detection — improved signal followed by high/critical annotation
- ChangeEvaluation — idempotent score+rationale per deployment
- Recurrence tracking — cycle count per widget, leaderboard
- AntifragilityDashboardAction (autoRefresh, 5 panels) per hub
- Phase 4 integration tests (T01–T08 logic coverage)
- docs/phase4-summary.md; SCOPE.md updated to Phase 4 complete

State Hub: workstream 07e9c860 → completed

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

Web/View/Hubs/GovernanceDashboard.hs

@@ -6,13 +6,14 @@ import IHP.Prelude
 import IHP.ViewPrelude
 
 data GovernanceDashboardView = GovernanceDashboardView
-    { hub              :: !Hub
-    , widgets          :: ![Widget]
-    , allCandidates    :: ![RequirementCandidate]
-    , allRequirements  :: ![Requirement]
-    , recentDecisions  :: ![DecisionRecord]
-    , allDecisions     :: ![DecisionRecord]
-    , allAnnotations   :: ![Annotation]
+    { hub                 :: !Hub
+    , widgets             :: ![Widget]
+    , allCandidates       :: ![RequirementCandidate]
+    , allRequirements     :: ![Requirement]
+    , recentDecisions     :: ![DecisionRecord]
+    , allDecisions        :: ![DecisionRecord]
+    , allAnnotations      :: ![Annotation]
+    , regressionWidgetIds :: ![Id Widget]
     }
 
 instance View GovernanceDashboardView where
@@ -33,6 +34,10 @@ instance View GovernanceDashboardView where
                    class="text-sm border border-gray-300 px-3 py-1.5 rounded hover:bg-gray-50">
                     Triage Dashboard
                 </a>
+                <a href={AntifragilityDashboardAction { hubId = hub.id }}
+                   class="text-sm border border-green-300 text-green-700 px-3 py-1.5 rounded hover:bg-green-50">
+                    Antifragility
+                </a>
                 <a href={ShowHubAction { hubId = hub.id }}
                    class="text-sm border border-gray-300 px-3 py-1.5 rounded hover:bg-gray-50">
                     Hub Overview
@@ -40,11 +45,24 @@ instance View GovernanceDashboardView where
             </div>
         </div>
 
-        <!-- KPI row: decision outcomes -->
-        <div class="grid grid-cols-3 gap-4 mb-6 sm:grid-cols-6">
+        <!-- KPI row: decision outcomes + regression -->
+        <div class="grid grid-cols-3 gap-4 mb-4 sm:grid-cols-7">
             {forEach outcomeList (\o -> renderKpiCard o (countOutcome allDecisions o))}
+            <div class="bg-red-50 text-red-800 rounded-lg px-4 py-3 text-center">
+                <div class="text-2xl font-bold">{show (length regressionWidgetIds)}</div>
+                <div class="text-xs mt-0.5 opacity-75">regressions</div>
+            </div>
         </div>
 
+        {if null regressionWidgetIds then mempty else [hsx|
+        <div class="bg-red-50 border border-red-200 rounded-lg px-6 py-4 mb-6">
+            <h2 class="text-sm font-semibold text-red-700 mb-2">⚠ Regressed Widgets</h2>
+            <div class="flex flex-wrap gap-2">
+                {forEach regressedWidgets renderRegressedBadge}
+            </div>
+        </div>
+        |]}
+
         <!-- Open requirements awaiting decision -->
         <div class="bg-white rounded-lg border border-gray-200 px-6 py-5 mb-6">
             <h2 class="text-sm font-semibold text-gray-700 mb-3">
@@ -99,7 +117,8 @@ instance View GovernanceDashboardView where
         </div>
     |]
   where
-    awaitingDecision = filter (isAwaitingDecision allDecisions) allRequirements
+    awaitingDecision  = filter (isAwaitingDecision allDecisions) allRequirements
+    regressedWidgets  = filter (\w -> w.id `elem` regressionWidgetIds) widgets
 
 outcomeList :: [Text]
 outcomeList = ["accepted", "rejected", "deferred", "split", "merged", "reframed"]
@@ -192,6 +211,14 @@ renderCoverageRow annotations candidates requirements decisions w = [hsx|
     widgetReqIds = map (.id) (filter (\r -> r.sourceCandidateId `elem` candidateIds) requirements)
     hasDecision  = any (\d -> d.requirementId `elem` map Just widgetReqIds) decisions
 
+renderRegressedBadge :: Widget -> Html
+renderRegressedBadge w = [hsx|
+    <a href={ShowWidgetAction { widgetId = w.id }}
+       class="text-xs bg-red-100 text-red-800 border border-red-300 rounded px-2 py-1 hover:bg-red-200">
+        {w.name}
+    </a>
+|]
+
 coverageMark :: Bool -> Html
 coverageMark True  = [hsx|<span class="text-green-600 font-bold">✓</span>|]
 coverageMark False = [hsx|<span class="text-gray-300">✗</span>|]