feat: Gluetun VPN integration and remote service enhancements

Major features:
- Native Docker-based Gluetun VPN proxy provider with multi-provider support
  (NordVPN, Windscribe, Surfshark, ExpressVPN, and 50+ more)
- Stateless remote service architecture with local session caching
- Client-side authentication for remote services (browser, 2FA, OAuth support)

Key changes:
- core/proxies/windscribevpn.py: Enhanced proxy handling
- core/crypto.py: Cryptographic utilities
- docs/VPN_PROXY_SETUP.md: Comprehensive VPN/proxy documentation

uv.lock

@@ -1090,6 +1090,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/b1/ec/1fb891d8a2660716aadb2143235481d15ed1cbfe3ad669194690b0604492/pycountry-24.6.1-py3-none-any.whl", hash = "sha256:f1a4fb391cd7214f8eefd39556d740adcc233c778a27f8942c8dca351d6ce06f", size = 6335189, upload-time = "2024-06-01T04:11:49.711Z" },
 ]
 
+[[package]]
+name = "pycountry"
+version = "24.6.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/76/57/c389fa68c50590881a75b7883eeb3dc15e9e73a0fdc001cdd45c13290c92/pycountry-24.6.1.tar.gz", hash = "sha256:b61b3faccea67f87d10c1f2b0fc0be714409e8fcdcc1315613174f6466c10221", size = 6043910, upload-time = "2024-06-01T04:12:15.05Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/b1/ec/1fb891d8a2660716aadb2143235481d15ed1cbfe3ad669194690b0604492/pycountry-24.6.1-py3-none-any.whl", hash = "sha256:f1a4fb391cd7214f8eefd39556d740adcc233c778a27f8942c8dca351d6ce06f", size = 6335189, upload-time = "2024-06-01T04:11:49.711Z" },
+]
+
 [[package]]
 name = "pycparser"
 version = "2.22"