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/Controller/Hubs.hs

@@ -7,9 +7,11 @@ import Web.View.Hubs.New
 import Web.View.Hubs.Edit
 import Web.View.Hubs.TriageDashboard
 import Web.View.Hubs.GovernanceDashboard
+import Web.View.Hubs.AntifragilityDashboard
 import Generated.Types
 import IHP.Prelude
 import IHP.ControllerPrelude
+import Application.Helper.Controller (regressedWidgetIds, widgetCycleCounts)
 
 instance Controller HubsController where
     beforeAction = ensureIsUser
@@ -147,6 +149,13 @@ instance Controller HubsController where
             |> filterWhereIn (#widgetId, widgetIds)
             |> fetch
 
+        -- Outcome signals for regression detection
+        allSignals <- query @OutcomeSignal
+            |> filterWhereIn (#widgetId, widgetIds)
+            |> fetch
+
+        let regressionWidgetIds = regressedWidgetIds allSignals allAnnotations
+
         render GovernanceDashboardView
             { hub
             , widgets
@@ -155,4 +164,58 @@ instance Controller HubsController where
             , recentDecisions
             , allDecisions
             , allAnnotations
+            , regressionWidgetIds
+            }
+
+    action AntifragilityDashboardAction { hubId } = autoRefresh do
+        hub     <- fetch hubId
+        widgets <- query @Widget
+            |> filterWhere (#hubId, hubId)
+            |> fetch
+        let widgetIds = map (.id) widgets
+
+        -- Deployments for this hub's decisions
+        allCandidates <- query @RequirementCandidate
+            |> filterWhereIn (#sourceWidgetId, widgetIds)
+            |> fetch
+        let acceptedCandidateIds = map (.id) (filter (\c -> c.status == "accepted") allCandidates)
+        allRequirements <- query @Requirement
+            |> filterWhereIn (#sourceCandidateId, acceptedCandidateIds)
+            |> fetch
+        let requirementIds = map (.id) allRequirements
+        allDecisions <- query @DecisionRecord
+            |> filterWhereIn (#requirementId, map Just requirementIds)
+            |> fetch
+        let decisionIds = map (.id) allDecisions
+        allDeployments <- query @DeploymentRecord
+            |> filterWhereIn (#decisionId, decisionIds)
+            |> orderByDesc #deployedAt
+            |> fetch
+        let deploymentIds = map (.id) allDeployments
+        allSignals <- query @OutcomeSignal
+            |> filterWhereIn (#widgetId, widgetIds)
+            |> fetch
+        allEvaluations <- query @ChangeEvaluation
+            |> filterWhereIn (#deploymentId, deploymentIds)
+            |> fetch
+        allImplRefs <- query @ImplementationChangeReference
+            |> filterWhereIn (#decisionId, decisionIds)
+            |> fetch
+        allAnnotations <- query @Annotation
+            |> filterWhereIn (#widgetId, widgetIds)
+            |> fetch
+
+        let regressionWidgetIds     = regressedWidgetIds allSignals allAnnotations
+            recurrenceLeaderboard   = take 10 (widgetCycleCounts allCandidates allRequirements allDecisions allDeployments)
+
+        render AntifragilityDashboardView
+            { hub
+            , widgets
+            , allDeployments
+            , allDecisions
+            , allSignals
+            , allEvaluations
+            , allImplRefs
+            , regressionWidgetIds
+            , recurrenceLeaderboard
             }