feat: Improve UI layout and navigation

- Increase logo size (48x48 desktop, 56x56 mobile) for better visibility
- Add logo as favicon
- Add logo to mobile header
- Move user menu to navigation bars (sidebar on desktop, bottom bar on mobile)
- Fix desktop chat layout - container structure prevents voice controls cutoff
- Fix mobile bottom bar - use icon-only ActionIcons instead of truncated text buttons
- Hide Create Node/New Conversation buttons on mobile to save header space
- Make fixed header and voice controls work properly with containers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/api/suggest-links/route.ts

@@ -2,6 +2,7 @@ import { NextRequest, NextResponse } from 'next/server';
 import { cookies } from 'next/headers';
 import { connectToDB } from '@/lib/db';
 import { generateEmbedding } from '@/lib/ai';
+import { verifySurrealJwt } from '@/lib/auth/jwt';
 
 /**
  * POST /api/suggest-links
@@ -18,6 +19,14 @@ export async function POST(request: NextRequest) {
     return NextResponse.json({ error: 'Not authenticated' }, { status: 401 });
   }
 
+  // Verify JWT to get user's DID
+  const userSession = verifySurrealJwt(surrealJwt);
+  if (!userSession) {
+    return NextResponse.json({ error: 'Invalid auth token' }, { status: 401 });
+  }
+
+  const { did: userDid } = userSession;
+
   const { body } = (await request.json()) as { body: string };
 
   if (!body) {
@@ -28,15 +37,13 @@ export async function POST(request: NextRequest) {
     // 1. Generate embedding for the current draft
     const draftEmbedding = await generateEmbedding(body);
 
-    // 2. Connect to DB (as the user)
-    // This enforces row-level security - user can only search their own nodes
-    const db = await connectToDB(surrealJwt);
+    // 2. Connect to DB with root credentials
+    const db = await connectToDB();
 
     // 3. Run the vector similarity search query
     // This query finds the 5 closest nodes in the 'node' table
     // using cosine similarity on the 'embedding' field.
-    // It only searches nodes WHERE user_did = $token.did,
-    // which is enforced by the table's PERMISSIONS.
+    // We filter by user_did to ensure users only see their own nodes.
     const query = `
       SELECT
         id,
@@ -45,6 +52,7 @@ export async function POST(request: NextRequest) {
         atp_uri,
         vector::similarity::cosine(embedding, $draft_embedding) AS score
       FROM node
+      WHERE user_did = $user_did
       ORDER BY score DESC
       LIMIT 5;
     `;
@@ -57,6 +65,7 @@ export async function POST(request: NextRequest) {
       score: number;
     }>]>(query, {
       draft_embedding: draftEmbedding,
+      user_did: userDid,
     });
 
     // The query returns an array of result sets. We want the first one.