docs: update PRD with comprehensive extension features and UX integration strategy

- Added UX strategy: Extension for Quick Actions, Frontend for Management
- Organized features into 4 phases (Phase 1 completed)
- Added 14 new extension features (FR-EXT-07 to FR-EXT-17):
  * Smart Monitoring: Price alerts, whale tracking, rug pull detection
  * Trading Intelligence: Token analysis, entry/exit suggestions, portfolio tracker
  * Content Creation: Chart screenshots, AI thread generator
  * Productivity: Quick actions, notifications, keyboard shortcuts
- Added Feature Responsibility Matrix showing Extension vs Frontend roles
- Added Settings Sync strategy (FR-EXT-06) with deep links to frontend
- Documented state sync architecture: Extension ↔ Backend API ↔ Frontend

surfsense_browser_extension/sidepanel/chat/ChatMessages.tsx

@@ -0,0 +1,33 @@
+/**
+ * Chat messages display component
+ */
+export function ChatMessages({ messages }: { messages: any[] }) {
+    if (messages.length === 0) {
+        return (
+            <div className="flex items-center justify-center h-full text-muted-foreground">
+                <p>Start a conversation...</p>
+            </div>
+        );
+    }
+
+    return (
+        <div className="p-4 space-y-4">
+            {messages.map((message) => (
+                <div
+                    key={message.id}
+                    className={`flex ${message.role === "user" ? "justify-end" : "justify-start"
+                        }`}
+                >
+                    <div
+                        className={`max-w-[80%] rounded-lg p-3 ${message.role === "user"
+                                ? "bg-primary text-primary-foreground"
+                                : "bg-muted"
+                            }`}
+                    >
+                        <p className="text-sm">{message.content}</p>
+                    </div>
+                </div>
+            ))}
+        </div>
+    );
+}