Flatten repo structure: move crawler/ to root, remove vqa/ and immoweb/

The crawler subdirectory was the only active project. Moving it to the
repo root simplifies paths and removes the unnecessary nesting. The
vqa/ and immoweb/ directories were legacy/unused and have been removed.

Updated .drone.yml, .gitignore, .claude/ docs, and skills to reflect
the new flat structure.

api/passkey_routes.py

@@ -0,0 +1,93 @@
+import logging
+
+from fastapi import APIRouter, HTTPException
+from pydantic import BaseModel, EmailStr
+
+from database import engine
+from repositories.user_repository import UserRepository
+from services import passkey_service
+
+logger = logging.getLogger("uvicorn")
+
+passkey_router = APIRouter(prefix="/api/passkey", tags=["passkey"])
+
+
+class RegisterBeginRequest(BaseModel):
+    email: EmailStr
+
+
+class RegisterBeginResponse(BaseModel):
+    options: dict  # type: ignore[type-arg]
+    session_id: str
+
+
+class CeremonyCompleteRequest(BaseModel):
+    session_id: str
+    credential: dict  # type: ignore[type-arg]
+
+
+class AuthTokenResponse(BaseModel):
+    token: str
+
+
+class LoginBeginResponse(BaseModel):
+    options: dict  # type: ignore[type-arg]
+    session_id: str
+
+
+@passkey_router.post("/register/begin", response_model=RegisterBeginResponse)
+async def register_begin(body: RegisterBeginRequest) -> RegisterBeginResponse:
+    """Start passkey registration ceremony."""
+    try:
+        user_repo = UserRepository(engine)
+        options, session_id = passkey_service.begin_registration(
+            body.email, user_repo
+        )
+        return RegisterBeginResponse(options=options, session_id=session_id)
+    except Exception as e:
+        logger.error(f"Registration begin failed: {e}")
+        raise HTTPException(status_code=400, detail=str(e))
+
+
+@passkey_router.post("/register/complete", response_model=AuthTokenResponse)
+async def register_complete(body: CeremonyCompleteRequest) -> AuthTokenResponse:
+    """Complete passkey registration ceremony."""
+    try:
+        user_repo = UserRepository(engine)
+        token = passkey_service.complete_registration(
+            body.session_id, body.credential, user_repo
+        )
+        return AuthTokenResponse(token=token)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Registration complete failed: {e}")
+        raise HTTPException(status_code=400, detail=str(e))
+
+
+@passkey_router.post("/login/begin", response_model=LoginBeginResponse)
+async def login_begin() -> LoginBeginResponse:
+    """Start passkey authentication ceremony."""
+    try:
+        user_repo = UserRepository(engine)
+        options, session_id = passkey_service.begin_authentication(user_repo)
+        return LoginBeginResponse(options=options, session_id=session_id)
+    except Exception as e:
+        logger.error(f"Login begin failed: {e}")
+        raise HTTPException(status_code=400, detail=str(e))
+
+
+@passkey_router.post("/login/complete", response_model=AuthTokenResponse)
+async def login_complete(body: CeremonyCompleteRequest) -> AuthTokenResponse:
+    """Complete passkey authentication ceremony."""
+    try:
+        user_repo = UserRepository(engine)
+        token = passkey_service.complete_authentication(
+            body.session_id, body.credential, user_repo
+        )
+        return AuthTokenResponse(token=token)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Login complete failed: {e}")
+        raise HTTPException(status_code=400, detail=str(e))