feat: add sources CRUD API with tests

- Full CRUD endpoints for backup sources
- Pydantic validation for source types
- pytest tests for create, list, get, delete

backend/tests/test_sources.py

@@ -0,0 +1,64 @@
+import pytest
+from httpx import AsyncClient
+from app.main import app
+
+@pytest.mark.asyncio
+async def test_create_source():
+    async with AsyncClient(app=app, base_url="http://test") as ac:
+        response = await ac.post("/api/sources/", json={
+            "name": "Test Source",
+            "type": "local",
+            "config": {"path": "/tmp/test"}
+        })
+    assert response.status_code == 200
+    data = response.json()
+    assert data["name"] == "Test Source"
+    assert data["type"] == "local"
+    assert "id" in data
+
+@pytest.mark.asyncio
+async def test_list_sources():
+    async with AsyncClient(app=app, base_url="http://test") as ac:
+        # Create source first
+        await ac.post("/api/sources/", json={
+            "name": "Test Source",
+            "type": "local",
+            "config": {"path": "/tmp/test"}
+        })
+        
+        response = await ac.get("/api/sources/")
+    assert response.status_code == 200
+    data = response.json()
+    assert len(data) >= 1
+
+@pytest.mark.asyncio
+async def test_get_source():
+    async with AsyncClient(app=app, base_url="http://test") as ac:
+        create_resp = await ac.post("/api/sources/", json={
+            "name": "Test Source",
+            "type": "local",
+            "config": {"path": "/tmp/test"}
+        })
+        source_id = create_resp.json()["id"]
+        
+        response = await ac.get(f"/api/sources/{source_id}")
+    assert response.status_code == 200
+    assert response.json()["id"] == source_id
+
+@pytest.mark.asyncio
+async def test_delete_source():
+    async with AsyncClient(app=app, base_url="http://test") as ac:
+        create_resp = await ac.post("/api/sources/", json={
+            "name": "Delete Me",
+            "type": "local",
+            "config": {"path": "/tmp/test"}
+        })
+        source_id = create_resp.json()["id"]
+        
+        response = await ac.delete(f"/api/sources/{source_id}")
+    assert response.status_code == 200
+    
+    # Verify deletion
+    async with AsyncClient(app=app, base_url="http://test") as ac:
+        get_resp = await ac.get(f"/api/sources/{source_id}")
+    assert get_resp.status_code == 404