Implement Gemini batch sentiment scoring; replace FinBERT/transformers

- Migrate news_engine to google-genai SDK with gemini-2.5-flash-lite
- Batch all headlines into one API call per scan (30 calls -> 1)
- In-memory cache keyed by headline hash; fallback to keyword scoring
- Update requirements.txt: add google-genai, python-dotenv; remove transformers
- Add .gitignore; update CLAUDE.md with Gemini live section

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

requirements.txt

@@ -1,5 +1,18 @@
+# Core data + math
 numpy>=1.24
 pandas>=2.0
+
+# HTTP
 requests>=2.28
-yfinance>=0.2.40
+curl_cffi>=0.7         # required by yfinance for impersonated TLS + verify=False
+                       # on TLS-inspecting servers
+
+# Market data
+yfinance>=0.2.40       # XAU/XAG (uses GC=F / SI=F futures via curl_cffi)
+
+# News sentiment (Gemini LLM)
+google-genai>=1.0      # new unified Google GenAI SDK (replaces google-generativeai)
+python-dotenv>=1.0     # loads GEMINI_API_KEY from .env
+
+# Telegram bot
 python-telegram-bot[job-queue]>=20.0