Switch back to JDK WebSocket (#321)

Unfortunately, using Netty for web sockets creates possible headaches
for specific frameworks. For example, Helidon is using netty 4.1 but we
are on netty 4.2. Switching to the JDK provided WebSocket eliminates
this issue.

Unfortunately, there is one inefficiency from switching to JDK
WebSocket. The `onText` message receives the text in UTF-16 though it
was passed on the wire as UTF-8. Given that the import/export messages
pass gzipped, base-64 encoded Strings, the UTF-8 to 16 transform is not
needed. However, probably better to change Conductor to use binary
messages for import request / export response which would eliminate the
base64 encoding.

Author: devhawk

transact/build.gradle.kts

@@ -28,15 +28,12 @@ tasks.named("build") { dependsOn("javadoc") }
 dependencies {
   api("org.slf4j:slf4j-api:2.0.17") // logging api
   api("org.jspecify:jspecify:1.0.0")
-  api(platform("io.netty:netty-bom:4.2.10.Final")) // export Netty version constraints to consumers
 
   implementation("org.postgresql:postgresql:42.7.10")
   implementation("com.zaxxer:HikariCP:7.0.2") // Connection pool
   implementation("com.fasterxml.jackson.core:jackson-databind:2.21.1") // json
   implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.21.1")
   implementation("com.cronutils:cron-utils:9.2.1") // cron for scheduled wf
-  implementation("io.netty:netty-codec-http") // HTTP and WebSocket codecs
-  implementation("io.netty:netty-handler") // SSL and channel handlers
 
   testImplementation(platform("org.junit:junit-bom:6.0.3"))
   testImplementation("org.junit.jupiter:junit-jupiter")