feat: journal dashboard widgets, agent polish, and edit-mode live previews

Journal dashboard widgets and quick-add; rich-text quick-add dialogs.

Dashboard draft sync for live edit previews; assistant bubble + API tools.

Journal UX: stress slider, mood grid, query cap fix.

src/app/api/agent/chat/route.ts

@@ -1,10 +1,13 @@
 import { z } from "zod";
 import { apiError, apiJson } from "@/lib/api-handler";
 import { resolveApiAuth } from "@/lib/api-auth";
+import { getAssistantEnabled } from "@/lib/assistant-preference";
 import { isLlmConfigured } from "@/lib/llm";
+import { encodeSseEvent } from "@/modules/agent/server/progress";
 import { runAgentChat } from "@/modules/agent/server/run";
 
 const chatInput = z.object({
+  stream: z.boolean().optional(),
   messages: z
     .array(
       z.object({
@@ -18,10 +21,15 @@ const chatInput = z.object({
 
 export async function POST(request: Request) {
   const auth = await resolveApiAuth(request);
-  if (!auth) {
+  if (!auth?.userId) {
     return apiError("Unauthorized", 401);
   }
 
+  const assistantEnabled = await getAssistantEnabled(auth.userId);
+  if (!assistantEnabled) {
+    return apiError("Assistant not enabled", 403);
+  }
+
   let body: unknown;
   try {
     body = await request.json();
@@ -34,6 +42,47 @@ export async function POST(request: Request) {
     return apiError(parsed.error.issues[0]?.message ?? "Validation error", 400);
   }
 
+  if (parsed.data.stream) {
+    const stream = new ReadableStream<Uint8Array>({
+      async start(controller) {
+        const encoder = new TextEncoder();
+        const send = (event: Parameters<typeof encodeSseEvent>[0]) => {
+          controller.enqueue(encoder.encode(encodeSseEvent(event)));
+        };
+
+        try {
+          const result = await runAgentChat({
+            messages: parsed.data.messages,
+            request,
+            onProgress: send,
+          });
+
+          send({
+            type: "done",
+            message: {
+              role: "assistant",
+              content: result.message.content,
+            },
+            toolCalls: result.toolCalls,
+          });
+        } catch (err) {
+          const message = err instanceof Error ? err.message : "Agent request failed";
+          send({ type: "error", message });
+        } finally {
+          controller.close();
+        }
+      },
+    });
+
+    return new Response(stream, {
+      headers: {
+        "Content-Type": "text/event-stream; charset=utf-8",
+        "Cache-Control": "no-cache, no-transform",
+        Connection: "keep-alive",
+      },
+    });
+  }
+
   try {
     const result = await runAgentChat({
       messages: parsed.data.messages,