fix(e2e): Add retry logic for KV eventual consistency in session tests

The session-race.spec.ts E2E tests were failing in CI because they
expected session data to be immediately available after creation.
Cloudflare KV has eventual consistency, so data may not be available
on first read.

Added retry logic (3 attempts with 2-second waits) to all tests that
verify session data via API:
- "loaded session data persists after initial load"
- "session data survives rapid page refresh"
- "edits made after load are saved correctly"

Also added debug logging to help diagnose any future consistency issues.

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

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

Author: adewale

app/e2e/session-race.spec.ts

@@ -92,10 +92,22 @@ test.describe('Session Loading Race Condition', () => {
     await expect(page.locator('.track-row')).toHaveCount(2);
 
     // Verify via API that the session still has correct data
-    const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
-    expect(verifyRes.ok()).toBe(true);
+    // Retry logic for KV eventual consistency
+    let sessionData;
+    for (let attempt = 0; attempt < 3; attempt++) {
+      const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
+      expect(verifyRes.ok()).toBe(true);
+      sessionData = await verifyRes.json();
+      if (sessionData.tracks && sessionData.tracks.length > 0) break;
+      console.log(`[TEST] Retry ${attempt + 1}: tracks undefined, waiting...`);
+      await page.waitForTimeout(2000);
+    }
+
+    // Log actual response for debugging
+    if (!sessionData.tracks) {
+      console.log('[TEST] Session data after retries:', JSON.stringify(sessionData, null, 2));
+    }
 
-    const sessionData = await verifyRes.json();
     expect(sessionData.tracks).toHaveLength(2);
     expect(sessionData.tracks[0].id).toBe('race-track-1');
     expect(sessionData.tracks[1].id).toBe('race-track-2');
@@ -147,9 +159,20 @@ test.describe('Session Loading Race Condition', () => {
     // Should still have 1 track
     await expect(page.locator('.track-row')).toHaveCount(1);
 
-    // Verify via API
-    const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
-    const sessionData = await verifyRes.json();
+    // Verify via API with retry for KV consistency
+    let sessionData;
+    for (let attempt = 0; attempt < 3; attempt++) {
+      const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
+      sessionData = await verifyRes.json();
+      if (sessionData.tracks && sessionData.tracks.length > 0) break;
+      console.log(`[TEST] Retry ${attempt + 1}: tracks undefined, waiting...`);
+      await page.waitForTimeout(2000);
+    }
+
+    if (!sessionData.tracks) {
+      console.log('[TEST] Session data after retries:', JSON.stringify(sessionData, null, 2));
+    }
+
     expect(sessionData.tracks).toHaveLength(1);
     expect(sessionData.tracks[0].id).toBe('refresh-track');
     expect(sessionData.tempo).toBe(128);
@@ -208,9 +231,20 @@ test.describe('Session Loading Race Condition', () => {
 
     expect(isActive).toBe(true);
 
-    // Also verify via API
-    const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
-    const sessionData = await verifyRes.json();
+    // Also verify via API with retry for KV consistency
+    let sessionData;
+    for (let attempt = 0; attempt < 3; attempt++) {
+      const verifyRes = await request.get(`${API_BASE}/api/sessions/${sessionId}`);
+      sessionData = await verifyRes.json();
+      if (sessionData.tracks && sessionData.tracks.length > 0) break;
+      console.log(`[TEST] Retry ${attempt + 1}: tracks undefined, waiting...`);
+      await page.waitForTimeout(2000);
+    }
+
+    if (!sessionData.tracks) {
+      console.log('[TEST] Session data after retries:', JSON.stringify(sessionData, null, 2));
+    }
+
     expect(sessionData.tracks[0].steps[0]).toBe(true);
   });