Adapt Pinscope to DeepSeek, auto datasheets, and a shared library.

Based on manvalan/pinscope main. Default LLM is DeepSeek with local
skills and PDF ingest. Datasheets are fetched from LCSC/TI, stored in
the component library, and review extracts abs-max with a deeper
checklist. Adds scripts/update-pinscope.sh for the production host.

backend/requirements.txt

@@ -1,5 +1,6 @@
 fastapi>=0.115
 uvicorn[standard]
+openai>=1.60
 anthropic>=0.83
 google-genai>=1.59
 pydantic[email]>=2.0
@@ -12,6 +13,7 @@ google-cloud-storage>=2.14
 google-cloud-run>=0.10
 google-api-python-client>=2.100
 pypdf>=4.0
+pymupdf>=1.24
 PyJWT[crypto]>=2.8
 cryptography>=42.0
-packaging>=23.0
+httpx>=0.27