feat: add config processor mapping parsed config to NatsOptions

Port of Go server/opts.go processConfigFileLine switch. Maps parsed
NATS config dictionaries to NatsOptions fields including:
- Core options (port, host, server_name, limits, ping, write_deadline)
- Logging (debug, trace, logfile, log rotation)
- Authorization (single user, users array with permissions)
- TLS (cert/key/ca, verify, pinned_certs, handshake_first)
- Monitoring (http_port, https_port, http/https listen, base_path)
- Lifecycle (lame_duck_duration/grace_period)
- Server tags, file paths, system account options

Includes error collection (not fail-fast), duration parsing (ms/s/m/h
strings and numeric seconds), host:port listen parsing, and 56 tests
covering all config sections plus validation edge cases.

tests/NATS.Server.Tests/TestData/tls.conf

@@ -0,0 +1,12 @@
+tls {
+  cert_file: "/path/to/cert.pem"
+  key_file: "/path/to/key.pem"
+  ca_file: "/path/to/ca.pem"
+  verify: true
+  verify_and_map: true
+  timeout: 3
+  connection_rate_limit: 100
+  pinned_certs: ["abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789"]
+  handshake_first: true
+}
+allow_non_tls: false