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/voice-mode.spec.ts

@@ -0,0 +1,143 @@
+import { test, expect } from '@playwright/test';
+
+test.describe('Voice Mode', () => {
+  test.beforeEach(async ({ page }) => {
+    // Navigate to chat page (should be authenticated via setup)
+    await page.goto('/chat');
+    await expect(page.getByText('Ponderants Interview')).toBeVisible();
+  });
+
+  test('should start voice conversation and display correct button text', async ({ page }) => {
+    // Initial state - button should show "Start Voice Conversation"
+    const voiceButton = page.getByRole('button', { name: /Start Voice Conversation/i });
+    await expect(voiceButton).toBeVisible();
+
+    // Click to start voice mode
+    await voiceButton.click();
+
+    // Button should transition to one of the active states
+    // Could be "Generating speech..." if there's a greeting, or "Listening..." if no greeting
+    await expect(page.getByRole('button', { name: /Generating speech|Listening|Checking for greeting/i })).toBeVisible({
+      timeout: 5000,
+    });
+  });
+
+  test('should skip audio during generation and transition to listening', async ({ page }) => {
+    // Start voice mode
+    const voiceButton = page.getByRole('button', { name: /Start Voice Conversation/i });
+    await voiceButton.click();
+
+    // Wait for generation or playing state
+    await expect(page.getByRole('button', { name: /Generating speech|AI is speaking/i })).toBeVisible({
+      timeout: 5000,
+    });
+
+    // Skip button should be visible
+    const skipButton = page.getByRole('button', { name: /Skip/i });
+    await expect(skipButton).toBeVisible();
+
+    // Click skip
+    await skipButton.click();
+
+    // Should transition to listening state
+    await expect(page.getByRole('button', { name: /Listening/i })).toBeVisible({ timeout: 3000 });
+  });
+
+  test('should use test buttons to simulate full conversation flow', async ({ page }) => {
+    // Start voice mode
+    await page.getByRole('button', { name: /Start Voice Conversation/i }).click();
+
+    // Wait for initial state (could be checking, generating, or listening)
+    await page.waitForTimeout(1000);
+
+    // If there's a skip button (greeting is playing), click it
+    const skipButton = page.getByRole('button', { name: /Skip/i });
+    if (await skipButton.isVisible()) {
+      await skipButton.click();
+    }
+
+    // Should eventually reach listening state
+    await expect(page.getByRole('button', { name: /Listening/i })).toBeVisible({ timeout: 5000 });
+
+    // In development mode, test buttons should be visible
+    const isDevelopment = process.env.NODE_ENV !== 'production';
+    if (isDevelopment) {
+      // Click "Simulate User Speech" test button
+      const simulateSpeechButton = page.getByRole('button', { name: /Simulate Speech/i });
+      await expect(simulateSpeechButton).toBeVisible();
+      await simulateSpeechButton.click();
+
+      // Should transition to userSpeaking state
+      await expect(page.getByRole('button', { name: /Speaking/i })).toBeVisible({ timeout: 2000 });
+
+      // Add a phrase using test button
+      const addPhraseButton = page.getByRole('button', { name: /Add Phrase/i });
+      await addPhraseButton.click();
+
+      // Should be in timingOut state
+      await expect(page.getByRole('button', { name: /auto-submit/i })).toBeVisible({ timeout: 2000 });
+
+      // Trigger timeout using test button
+      const triggerTimeoutButton = page.getByRole('button', { name: /Trigger Timeout/i });
+      await triggerTimeoutButton.click();
+
+      // Should submit and wait for AI
+      await expect(page.getByRole('button', { name: /Submitting|Waiting for AI/i })).toBeVisible({
+        timeout: 2000,
+      });
+
+      // Wait for AI response (this will take a few seconds)
+      await expect(page.getByRole('button', { name: /Generating speech|AI is speaking/i })).toBeVisible({
+        timeout: 15000,
+      });
+
+      // Skip the AI audio
+      const skipAudioButton = page.getByRole('button', { name: /Skip/i });
+      if (await skipAudioButton.isVisible()) {
+        await skipAudioButton.click();
+      }
+
+      // Should return to listening
+      await expect(page.getByRole('button', { name: /Listening/i })).toBeVisible({ timeout: 3000 });
+    }
+  });
+
+  test('should stop voice mode and return to idle', async ({ page }) => {
+    // Start voice mode
+    const voiceButton = page.getByRole('button', { name: /Start Voice Conversation/i });
+    await voiceButton.click();
+
+    // Wait for active state
+    await page.waitForTimeout(1000);
+
+    // Click the button again to stop
+    await page.getByRole('button', { name: /Listening|Speaking|Generating|AI is speaking/i }).click();
+
+    // Should return to idle state
+    await expect(page.getByRole('button', { name: /Start Voice Conversation/i })).toBeVisible({
+      timeout: 2000,
+    });
+  });
+
+  test('should disable text input while voice mode is active', async ({ page }) => {
+    const textInput = page.getByPlaceholder(/type your thoughts here/i);
+
+    // Text input should be enabled initially
+    await expect(textInput).toBeEnabled();
+
+    // Start voice mode
+    await page.getByRole('button', { name: /Start Voice Conversation/i }).click();
+
+    // Wait for voice mode to activate
+    await page.waitForTimeout(1000);
+
+    // Text input should be disabled
+    await expect(textInput).toBeDisabled();
+
+    // Stop voice mode
+    await page.getByRole('button', { name: /Listening|Speaking|Generating|AI is speaking/i }).click();
+
+    // Text input should be enabled again
+    await expect(textInput).toBeEnabled();
+  });
+});