feat(feedback): implement user feedback collection system with email reporting

Backend:
- Add user_feedback table with RLS policy
- Create feedback submission API (multipart/form-data)
- Implement xlsx report generation with embedded images
- Add scheduled email delivery via Feishu SMTP
- Create HTML email templates (daily_report, no_feedback)

Frontend:
- Add feedback screen with type selection and image picker
- Support anonymous submission via skipAuth flag
- Collect device info and app version

Protocol:
- Document feedback API contract and error codes
- Update http-error-codes.md with FEEDBACK_* codes

backend/tests/integration/conftest_feedback.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import os
+import time
+
+import pytest
+
+
+def pytest_configure(config):  # noqa: ARG001
+    config.addinivalue_line(
+        "markers", "integration: integration test requiring live backend"
+    )
+
+
+def pytest_collection_modifyitems(items):
+    for item in items:
+        if "integration" in item.nodeid:
+            item.add_marker(pytest.mark.integration)
+
+
+@pytest.fixture(scope="session")
+def api_base_url() -> str:
+    return os.environ.get("ERYAO_TEST_BASE_URL", "http://localhost:5775")
+
+
+@pytest.fixture
+def unique_test_email() -> str:
+    base_email = os.environ.get("ERYAO_TEST__EMAIL", "test@example.com").strip().lower()
+    if "@" in base_email:
+        name, domain = base_email.split("@", 1)
+    else:
+        name, domain = base_email, "example.com"
+    return f"{name}+fb{int(time.time() * 1000)}@{domain}"
+
+
+@pytest.fixture
+def test_verify_code() -> str:
+    return os.environ.get("ERYAO_TEST__CODE", "123456")
+
+
+@pytest.fixture
+def test_identity(unique_test_email: str, test_verify_code: str) -> dict[str, str]:
+    return {"email": unique_test_email, "code": test_verify_code}

backend/tests/integration/test_feedback_submit.py

@@ -0,0 +1,159 @@
+from __future__ import annotations
+
+from collections.abc import AsyncIterator
+
+import httpx
+import pytest
+import json
+
+
+@pytest.fixture
+async def feedback_client(api_base_url: str) -> AsyncIterator[httpx.AsyncClient]:
+    async with httpx.AsyncClient(base_url=api_base_url, timeout=30.0) as client:
+        try:
+            health = await client.get("/health")
+            if health.status_code != 200:
+                pytest.skip(f"API not ready: /health={health.status_code}")
+        except Exception as exc:
+            pytest.skip(f"API unavailable: {exc}")
+        yield client
+
+
+@pytest.fixture
+async def authed_feedback_client(
+    feedback_client: httpx.AsyncClient,
+    test_identity: dict[str, str],
+) -> httpx.AsyncClient:
+    otp_response = await feedback_client.post(
+        "/api/v1/auth/otp",
+        json={"email": test_identity["email"]},
+    )
+    if otp_response.status_code not in (200, 204):
+        pytest.skip(f"OTP request failed: {otp_response.status_code}")
+
+    verify_response = await feedback_client.post(
+        "/api/v1/auth/verify",
+        json={
+            "email": test_identity["email"],
+            "code": test_identity["code"],
+        },
+    )
+    if verify_response.status_code != 200:
+        pytest.skip(f"Auth verify failed: {verify_response.status_code}")
+
+    token = verify_response.json().get("access_token") or verify_response.json().get(
+        "session", {}
+    ).get("access_token")
+    if not token:
+        pytest.skip("No access token in auth response")
+
+    feedback_client.headers["Authorization"] = f"Bearer {token}"
+    return feedback_client
+
+
+class TestFeedbackSubmitAnonymous:
+    @pytest.mark.asyncio
+    async def test_submit_feedback_anonymous_success(
+        self, feedback_client: httpx.AsyncClient
+    ):
+        response = await feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "bug",
+                "content": "App crashes when opening settings",
+                "device_info": json.dumps({"platform": "ios", "model": "iPhone 15"}),
+                "app_version": "1.0.0",
+                "os_version": "iOS 17.0",
+            },
+        )
+        assert response.status_code == 201
+        body = response.json()
+        assert "id" in body
+        assert "created_at" in body
+
+    @pytest.mark.asyncio
+    async def test_submit_feedback_with_auth(
+        self, authed_feedback_client: httpx.AsyncClient
+    ):
+        response = await authed_feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "suggestion",
+                "content": "Please add dark mode",
+                "device_info": json.dumps({"platform": "android", "model": "Pixel 8"}),
+                "app_version": "1.0.0",
+                "os_version": "Android 14",
+            },
+        )
+        assert response.status_code == 201
+        body = response.json()
+        assert "id" in body
+        assert "created_at" in body
+
+    @pytest.mark.asyncio
+    async def test_submit_feedback_content_empty(
+        self, feedback_client: httpx.AsyncClient
+    ):
+        response = await feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "bug",
+                "content": "",
+                "device_info": json.dumps({"platform": "ios", "model": "iPhone 15"}),
+                "app_version": "1.0.0",
+                "os_version": "iOS 17.0",
+            },
+        )
+        assert response.status_code == 400
+        assert response.json().get("code") == "FEEDBACK_CONTENT_EMPTY"
+
+    @pytest.mark.asyncio
+    async def test_submit_feedback_content_too_long(
+        self, feedback_client: httpx.AsyncClient
+    ):
+        response = await feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "bug",
+                "content": "x" * 501,
+                "device_info": json.dumps({"platform": "ios", "model": "iPhone 15"}),
+                "app_version": "1.0.0",
+                "os_version": "iOS 17.0",
+            },
+        )
+        assert response.status_code == 400
+        assert response.json().get("code") == "FEEDBACK_CONTENT_TOO_LONG"
+
+    @pytest.mark.asyncio
+    async def test_submit_feedback_invalid_device_info(
+        self, feedback_client: httpx.AsyncClient
+    ):
+        response = await feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "bug",
+                "content": "Test content",
+                "device_info": "not-json",
+                "app_version": "1.0.0",
+                "os_version": "iOS 17.0",
+            },
+        )
+        assert response.status_code == 422
+
+    @pytest.mark.asyncio
+    async def test_submit_feedback_with_image(self, feedback_client: httpx.AsyncClient):
+        fake_image = b"\xff\xd8\xff\xe0" + b"\x00" * 100
+        response = await feedback_client.post(
+            "/api/v1/feedback",
+            data={
+                "feedback_type": "bug",
+                "content": "Screenshot of the issue",
+                "device_info": json.dumps({"platform": "ios", "model": "iPhone 15"}),
+                "app_version": "1.0.0",
+                "os_version": "iOS 17.0",
+            },
+            files=[("images", ("screenshot.jpg", fake_image, "image/jpeg"))],
+        )
+        assert response.status_code == 201
+        body = response.json()
+        assert "id" in body