feat(FN-3000): harden research lifecycle with idempotent cancel/retry and S

This merge hardens the research feature across the stack with idempotent cancel/retry logic and SSE support for real-time updates in `research-orchestrator` and `sse.ts`, while also applying UX improvements to `PlanningModeModal` and `ResearchTaskActionModal`. The core `research-store` received sign

Fusion-Task-Id: FN-3000

packages/dashboard/app/components/ResearchTaskActionModal.css

@@ -20,8 +20,6 @@
   flex-direction: column;
   gap: var(--space-xs);
   color: var(--text-muted);
-  font-size: 0.75rem;
-  letter-spacing: 0.03em;
   text-transform: uppercase;
 }
 
@@ -34,4 +32,22 @@
   .research-task-action-modal {
     width: min(100%, calc(100vw - (var(--space-md) * 2)));
   }
+
+  .research-task-action-modal__body {
+    gap: var(--space-lg);
+  }
+
+  .research-task-action-modal__preview {
+    padding: var(--space-lg);
+  }
+
+  .research-task-action-modal .modal-actions {
+    flex-direction: column;
+    align-items: stretch;
+    gap: var(--space-sm);
+  }
+
+  .research-task-action-modal .modal-actions .btn {
+    min-height: calc(var(--space-lg) * 2 + var(--space-xs));
+  }
 }

packages/dashboard/app/components/ResearchView.css

@@ -92,10 +92,6 @@
 }
 
 .research-view__history-item {
-  border: var(--btn-border-width) solid var(--border);
-  border-radius: var(--radius-sm);
-  background: var(--surface);
-  color: var(--text);
   text-align: left;
   padding: var(--space-sm);
   min-height: calc(var(--space-lg) * 2 + var(--space-xs));
@@ -104,22 +100,6 @@
   justify-content: center;
   gap: var(--space-xs);
   cursor: pointer;
-  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast), transform var(--transition-fast);
-}
-
-.research-view__history-item:hover {
-  background: var(--card-hover);
-  border-color: var(--todo);
-}
-
-.research-view__history-item:focus-visible {
-  outline: none;
-  border-color: var(--todo);
-  box-shadow: var(--focus-ring-strong);
-}
-
-.research-view__history-item:active {
-  transform: scale(0.97);
 }
 
 .research-view__history-item--active {
@@ -208,12 +188,10 @@
 .research-view__stat-label {
   color: var(--text-muted);
   text-transform: uppercase;
-  font-size: 0.6875rem;
 }
 
 .research-view__stat-value {
   font-family: var(--font-mono);
-  font-size: 0.8125rem;
 }
 
 .research-view__state--error {

packages/dashboard/app/components/ResearchView.tsx

@@ -307,7 +307,7 @@ export function ResearchView({ projectId, addToast, onOpenSettings, readinessVer
               <button
                 key={run.id}
                 type="button"
-                className={`research-view__history-item${selectedRunId === run.id ? " research-view__history-item--active" : ""}`}
+                className={`research-view__history-item card${selectedRunId === run.id ? " research-view__history-item--active" : ""}`}
                 onClick={() => setSelectedRunId(run.id)}
               >
                 <span className="card-id">{run.id}</span>