fix: admin logout clears only admin tokens + add signup token tests

- Fix admin header.html logout to not use localStorage.clear()
  which was clearing vendor/customer tokens too
- Add tests for signup access_token generation
- Test that token is returned in response
- Test that token can authenticate API calls
- Test that vendor_token cookie is set

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/templates/admin/partials/header.html

@@ -284,8 +284,10 @@ document.addEventListener('alpine:init', () => {
                     console.error('Logout API error (continuing anyway):', error);
                 })
                 .finally(() => {
-                    // Clear all tokens
+                    // Clear admin tokens only (not vendor or customer tokens)
-                    localStorage.clear();
+                    localStorage.removeItem('admin_token');
+                    localStorage.removeItem('admin_user');
+                    // Note: Do NOT use localStorage.clear() - it would clear vendor/customer tokens too
                     window.location.href = '/admin/login';
                 });
             }

tests/integration/api/v1/platform/test_signup.py

@@ -463,6 +463,128 @@ class TestCompleteSignupAPI:
         assert "redirect_url" in data
         assert "trial_ends_at" in data
 
+    def test_complete_signup_returns_access_token(
+        self, client, signup_session, mock_stripe_service, db
+    ):
+        """Test that completing signup returns a valid JWT access token for auto-login."""
+        # Create account
+        client.post(
+            "/api/v1/platform/signup/create-account",
+            json={
+                "session_id": signup_session,
+                "email": "token_test@example.com",
+                "password": "SecurePass123!",
+                "first_name": "Token",
+                "last_name": "Test",
+                "company_name": "Token Test Co",
+            },
+        )
+
+        # Setup payment
+        client.post(
+            "/api/v1/platform/signup/setup-payment",
+            json={"session_id": signup_session},
+        )
+
+        # Complete signup
+        response = client.post(
+            "/api/v1/platform/signup/complete",
+            json={
+                "session_id": signup_session,
+                "setup_intent_id": "seti_test_123",
+            },
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # Verify access_token is returned
+        assert "access_token" in data
+        assert data["access_token"] is not None
+        assert len(data["access_token"]) > 50  # JWT tokens are long
+
+    def test_complete_signup_token_can_authenticate(
+        self, client, signup_session, mock_stripe_service, db
+    ):
+        """Test that the returned access token can be used to authenticate API calls."""
+        # Create account
+        client.post(
+            "/api/v1/platform/signup/create-account",
+            json={
+                "session_id": signup_session,
+                "email": "auth_test@example.com",
+                "password": "SecurePass123!",
+                "first_name": "Auth",
+                "last_name": "Test",
+                "company_name": "Auth Test Co",
+            },
+        )
+
+        # Setup payment
+        client.post(
+            "/api/v1/platform/signup/setup-payment",
+            json={"session_id": signup_session},
+        )
+
+        # Complete signup
+        complete_response = client.post(
+            "/api/v1/platform/signup/complete",
+            json={
+                "session_id": signup_session,
+                "setup_intent_id": "seti_test_123",
+            },
+        )
+
+        assert complete_response.status_code == 200
+        access_token = complete_response.json()["access_token"]
+
+        # Use the token to access a protected vendor endpoint
+        auth_response = client.get(
+            "/api/v1/vendor/onboarding/status",
+            headers={"Authorization": f"Bearer {access_token}"},
+        )
+
+        # Should be able to access the onboarding endpoint
+        assert auth_response.status_code == 200
+
+    def test_complete_signup_sets_vendor_token_cookie(
+        self, client, signup_session, mock_stripe_service, db
+    ):
+        """Test that completing signup sets the vendor_token HTTP-only cookie."""
+        # Create account
+        client.post(
+            "/api/v1/platform/signup/create-account",
+            json={
+                "session_id": signup_session,
+                "email": "cookie_test@example.com",
+                "password": "SecurePass123!",
+                "first_name": "Cookie",
+                "last_name": "Test",
+                "company_name": "Cookie Test Co",
+            },
+        )
+
+        # Setup payment
+        client.post(
+            "/api/v1/platform/signup/setup-payment",
+            json={"session_id": signup_session},
+        )
+
+        # Complete signup
+        response = client.post(
+            "/api/v1/platform/signup/complete",
+            json={
+                "session_id": signup_session,
+                "setup_intent_id": "seti_test_123",
+            },
+        )
+
+        assert response.status_code == 200
+
+        # Check that vendor_token cookie is set
+        cookies = response.cookies
+        assert "vendor_token" in cookies
+
     def test_complete_signup_invalid_session(self, client, mock_stripe_service):
         """Test completing signup with invalid session."""
         response = client.post(