feat: Add Booklooker client configuration and exception handling

- Introduced BooklookerConfig class for runtime configuration management.
- Created custom exceptions for API errors, including authentication and validation errors.
- Generated API contracts from OpenAPI specification, including endpoints and security schemes.
- Implemented models for articles, orders, and webhooks to facilitate data handling.
- Developed a webhook helper for processing and enriching webhook events.
- Added tests for configuration defaults, token expiration, and webhook enrichment.

examples/webhook_fastapi.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+import os
+
+from fastapi import FastAPI, Request
+
+from booklooker_client import BooklookerConfig, BooklookerWebhookHelper, SyncBooklookerClient
+
+
+app = FastAPI(title="Booklooker webhook receiver")
+helper = BooklookerWebhookHelper()
+client = SyncBooklookerClient(BooklookerConfig(api_key=os.environ.get("BOOKLOOKER_API_KEY", "REPLACE_ME")))
+
+
+@app.post("/webhooks/booklooker")
+async def receive_booklooker_webhook(request: Request) -> dict:
+    payload = await request.json()
+    event = helper.enrich_with_client(payload, client)
+    return {"accepted": True, "event": event.model_dump(mode="json")}