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>

tests/magnitude/cache-success.mag.ts

@@ -0,0 +1,37 @@
+/**
+ * Magnitude Test: Cache Success
+ *
+ * This test verifies that node publishing succeeds with full cache write,
+ * not just a degraded state with warnings.
+ */
+
+import { test } from 'magnitude-test';
+
+test('Node publishes successfully with cache (no warnings)', async (agent) => {
+  await agent.open('http://localhost:3000');
+
+  // Login
+  await agent.act('Click the "Log in with Bluesky" button');
+  await agent.act('Fill in credentials and submit')
+    .data({
+      username: process.env.TEST_BLUESKY_USERNAME || 'test-user.bsky.social',
+      password: process.env.TEST_BLUESKY_PASSWORD || 'test-password',
+    });
+  await agent.check('Logged in successfully');
+
+  // Start conversation
+  await agent.act('Type "Test cache write success" and press Enter');
+  await agent.check('AI responds');
+
+  // Create and publish node
+  await agent.act('Click "Create Node"');
+  await agent.check('On edit page with draft');
+
+  await agent.act('Click "Publish Node"');
+
+  // CRITICAL: Should get green success notification, NOT yellow warning
+  await agent.check('Success notification is GREEN (not yellow warning)');
+  await agent.check('Notification says "Your node has been published to your Bluesky account"');
+  await agent.check('Notification does NOT mention "cache update failed"');
+  await agent.check('Notification does NOT mention "Advanced features may be unavailable"');
+});