feat: add Mihomo API client with refresh polling

Implements MihomoClient wrapping Mihomo's REST API with provider refresh
polling, config reload, and startup readiness check. Also fixes a
Python 3.14 + respx 0.21.1 compatibility issue where the httpcore mocker
passes bytes method to httpx.Request causing Method pattern matching to
fail; resolved by switching respx DEFAULT_MOCKER to the httpx-level mocker.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/tests/conftest.py

@@ -2,6 +2,14 @@ import sys
 import os
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
+import respx.mocks
+# Python 3.14 + httpx 0.28 compatibility: httpcore passes method as bytes,
+# but the httpcore mocker reconstructs httpx.Request with bytes method,
+# causing Method pattern comparison ('GET' == b'GET') to always fail.
+# Use the httpx-level mocker instead, which patches AsyncClient._transport_for_url
+# and avoids the bytes/str mismatch entirely.
+respx.mocks.DEFAULT_MOCKER = "httpx"
+
 import pytest_asyncio
 from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker
 from models import Base

app/tests/test_mihomo.py

@@ -0,0 +1,98 @@
+import pytest
+import respx
+import httpx
+from mihomo import MihomoClient
+
+
+@pytest.fixture
+def client():
+    return MihomoClient("http://mihomo:9090", "secret123")
+
+
+async def test_trigger_provider_refresh(client):
+    with respx.mock:
+        respx.put("http://mihomo:9090/providers/proxies/myprovider").mock(
+            return_value=httpx.Response(204)
+        )
+        await client.trigger_provider_refresh("myprovider")
+
+
+async def test_get_provider(client):
+    payload = {
+        "name": "myprovider",
+        "updatedAt": "2024-01-01T00:00:00Z",
+        "proxies": [{"name": "node1", "type": "ss"}],
+    }
+    with respx.mock:
+        respx.get("http://mihomo:9090/providers/proxies/myprovider").mock(
+            return_value=httpx.Response(200, json=payload)
+        )
+        data = await client.get_provider("myprovider")
+    assert data["updatedAt"] == "2024-01-01T00:00:00Z"
+
+
+async def test_refresh_and_collect_detects_update(client):
+    call_count = 0
+
+    def provider_handler(request):
+        nonlocal call_count
+        call_count += 1
+        if call_count == 1:
+            return httpx.Response(200, json={"updatedAt": "t1", "proxies": []})
+        return httpx.Response(
+            200,
+            json={
+                "updatedAt": "t2",
+                "proxies": [
+                    {"name": "n1", "type": "ss", "server": "1.2.3.4", "port": 443}
+                ],
+            },
+        )
+
+    with respx.mock:
+        respx.put("http://mihomo:9090/providers/proxies/myprovider").mock(
+            return_value=httpx.Response(204)
+        )
+        respx.get("http://mihomo:9090/providers/proxies/myprovider").mock(
+            side_effect=provider_handler
+        )
+        proxies = await client.refresh_and_collect("myprovider", timeout=5)
+
+    assert len(proxies) == 1
+    assert proxies[0]["name"] == "n1"
+
+
+async def test_refresh_and_collect_timeout(client):
+    with respx.mock:
+        respx.put("http://mihomo:9090/providers/proxies/slow").mock(
+            return_value=httpx.Response(204)
+        )
+        respx.get("http://mihomo:9090/providers/proxies/slow").mock(
+            return_value=httpx.Response(200, json={"updatedAt": "never-changes", "proxies": []})
+        )
+        with pytest.raises(TimeoutError):
+            await client.refresh_and_collect("slow", timeout=2)
+
+
+async def test_reload_config(client):
+    with respx.mock:
+        respx.put("http://mihomo:9090/configs").mock(return_value=httpx.Response(204))
+        await client.reload_config()
+
+
+async def test_wait_ready_succeeds(client):
+    with respx.mock:
+        respx.get("http://mihomo:9090/version").mock(
+            return_value=httpx.Response(200, json={"version": "1.0"})
+        )
+        await client.wait_ready(retries=3)
+
+
+async def test_wait_ready_raises_after_retries():
+    slow_client = MihomoClient("http://missing:9090", "")
+    with respx.mock:
+        respx.get("http://missing:9090/version").mock(
+            return_value=httpx.Response(503)
+        )
+        with pytest.raises(RuntimeError, match="did not become available"):
+            await slow_client.wait_ready(retries=2)