feat(config+ws): add TLS cert reload, WS compression negotiation, WS JWT auth (E9+E10+E11)
E9: TLS Certificate Reload
- Add TlsCertificateProvider with Interlocked-swappable cert field
- New connections get current cert, existing connections keep theirs
- ConfigReloader.ReloadTlsCertificate rebuilds SslServerAuthenticationOptions
- NatsServer.ApplyConfigChanges triggers TLS reload on TLS config changes
- 11 tests covering cert swap, versioning, thread safety, config diff
E10: WebSocket Compression Negotiation (RFC 7692)
- Add WsDeflateNegotiator to parse Sec-WebSocket-Extensions parameters
- Parse server_no_context_takeover, client_no_context_takeover,
server_max_window_bits, client_max_window_bits
- WsDeflateParams record struct with ToResponseHeaderValue()
- NATS always enforces no_context_takeover (matching Go server)
- WsUpgrade returns negotiated WsDeflateParams in upgrade result
- 22 tests covering parameter parsing, clamping, response headers
E11: WebSocket JWT Authentication
- Extract JWT from Authorization header (Bearer token), cookie, or ?jwt= query param
- Priority: Authorization header > cookie > query parameter
- WsUpgrade.TryUpgradeAsync now parses query string from request URI
- Add FailUnauthorizedAsync for 401 responses
- 24 tests covering all JWT extraction sources and priority ordering
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