feat: Python traffic generator with realistic varied HTTP/HTTPS traffic

- Replace curlimages/curl with Python stdlib traffic generator
- 200 requests, 10 workers, 16 scenario types:
  browsers (Chrome/Firefox/Safari/Edge/mobile), bots (Googlebot/Bing/curl/wget),
  GET/POST/HEAD/PUT/PATCH/DELETE/OPTIONS, HTTP + HTTPS
- Multiple SSL contexts (default, TLS1.2-only, TLS1.3-only, few_ciphers)
  → 4 distinct JA4/JA3 fingerprints per test run
- Realistic headers: Accept, Accept-Language, Sec-Fetch-*, Referer,
  X-Forwarded-For, Cookie, Cache-Control
- JSON payloads, form data, CORS preflights
- DB always reset (down -v) at start of each test run
- Enhanced Phase 5 checks: distinct UAs, method variety, JA4/JA3 counts + uniqueness

Results: 199/200 OK, 24 distinct UAs, 7 HTTP methods, TLS 1.2+1.3, 4 JA4 fingerprints

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/integration/traffic-gen/Dockerfile

@@ -0,0 +1,8 @@
+FROM python:3.12-alpine
+
+# No extra deps needed — stdlib only (urllib, ssl, concurrent.futures)
+WORKDIR /app
+COPY generate_traffic.py .
+
+# Keep container alive; traffic is triggered via docker compose exec
+ENTRYPOINT ["sleep", "infinity"]