fix(#338): Disable QuickCaptureWidget in production with Coming Soon

- Show Coming Soon placeholder in production for both widget versions
- Widget available in development mode only
- Added tests verifying environment-based behavior
- Use runtime check for testability (isDevelopment function vs constant)

Refs #338

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/src/components/dashboard/QuickCaptureWidget.tsx

@@ -3,8 +3,19 @@
 import { useState } from "react";
 import { Button } from "@mosaic/ui";
 import { useRouter } from "next/navigation";
+import { ComingSoon } from "@/components/ui/ComingSoon";
 
-export function QuickCaptureWidget(): React.JSX.Element {
+/**
+ * Check if we're in development mode (runtime check for testability)
+ */
+function isDevelopment(): boolean {
+  return process.env.NODE_ENV === "development";
+}
+
+/**
+ * Internal Quick Capture Widget implementation
+ */
+function QuickCaptureWidgetInternal(): React.JSX.Element {
   const [idea, setIdea] = useState("");
   const router = useRouter();
 
@@ -48,3 +59,27 @@ export function QuickCaptureWidget(): React.JSX.Element {
     </div>
   );
 }
+
+/**
+ * Quick Capture Widget (Dashboard version)
+ *
+ * In production: Shows Coming Soon placeholder
+ * In development: Full widget functionality
+ */
+export function QuickCaptureWidget(): React.JSX.Element {
+  // In production, show Coming Soon placeholder
+  if (!isDevelopment()) {
+    return (
+      <div className="bg-white rounded-lg shadow-sm border border-gray-200 p-6">
+        <ComingSoon
+          feature="Quick Capture"
+          description="Quickly jot down ideas for later organization. This feature is currently under development."
+          className="!p-0 !min-h-0"
+        />
+      </div>
+    );
+  }
+
+  // In development, show full widget functionality
+  return <QuickCaptureWidgetInternal />;
+}