[KYUUBI #7430] Remove chat engine

### Why are the changes needed?

Chat engine was introduced as an experimental feature, and never went into production-ready status.

### How was this patch tested?

Review.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #7430 from pan3793/rm-chat-engine.

Closes #7430

b955691 [Cheng Pan] Remove chat engine

Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: pan3793

LICENSE-binary

@@ -304,8 +304,6 @@ io.swagger.core.v3:swagger-jaxrs2
 io.swagger.core.v3:swagger-models
 io.vertx:vertx-core
 io.vertx:vertx-grpc
-com.squareup.retrofit2:retrofit
-com.squareup.okhttp3:okhttp
 org.apache.kafka:kafka-clients
 org.xerial:sqlite-jdbc
 com.openai:openai-java
@@ -347,9 +345,6 @@ org.codehaus.mojo:animal-sniffer-annotations
 org.slf4j:slf4j-api
 org.slf4j:jcl-over-slf4j
 org.slf4j:jul-over-slf4j
-com.theokanning.openai-gpt3-java:api
-com.theokanning.openai-gpt3-java:client
-com.theokanning.openai-gpt3-java:service
 org.checkerframework:checker-qual
 
 CDDL License 1.1

build/dist

@@ -287,7 +287,6 @@ mkdir -p "$DISTDIR/externals/engines/spark"
 mkdir -p "$DISTDIR/externals/engines/trino"
 mkdir -p "$DISTDIR/externals/engines/hive"
 mkdir -p "$DISTDIR/externals/engines/jdbc"
-mkdir -p "$DISTDIR/externals/engines/chat"
 mkdir -p "$DISTDIR/externals/engines/data-agent"
 echo "Kyuubi $VERSION $GITREVSTRING built for" > "$DISTDIR/RELEASE"
 echo "Java $JAVA_VERSION" >> "$DISTDIR/RELEASE"
@@ -352,18 +351,6 @@ for jar in $(ls "$DISTDIR/jars/"); do
   fi
 done
 
-# Copy chat engines
-cp "$KYUUBI_HOME/externals/kyuubi-chat-engine/target/kyuubi-chat-engine_${SCALA_VERSION}-${VERSION}.jar" "$DISTDIR/externals/engines/chat/"
-cp -r "$KYUUBI_HOME"/externals/kyuubi-chat-engine/target/scala-$SCALA_VERSION/jars/*.jar "$DISTDIR/externals/engines/chat/"
-
-# Share the jars w/ server to reduce binary size
-# shellcheck disable=SC2045
-for jar in $(ls "$DISTDIR/jars/"); do
-  if [[ -f "$DISTDIR/externals/engines/chat/$jar" ]]; then
-    (cd $DISTDIR/externals/engines/chat; ln -snf "../../../jars/$jar" "$DISTDIR/externals/engines/chat/$jar")
-  fi
-done
-
 # Copy data-agent engines
 cp "$KYUUBI_HOME/externals/kyuubi-data-agent-engine/target/kyuubi-data-agent-engine_${SCALA_VERSION}-${VERSION}.jar" "$DISTDIR/externals/engines/data-agent/"
 cp -r "$KYUUBI_HOME"/externals/kyuubi-data-agent-engine/target/scala-$SCALA_VERSION/jars/*.jar "$DISTDIR/externals/engines/data-agent/"

docs/configuration/settings.md

@@ -24,6 +24,7 @@
 * Since Kyuubi 1.12, session configurations in REST API responses are redacted by default using `kyuubi.server.redaction.regex`. Use `kyuubi.server.conf.retrieveMode` to control this behavior: `REDACTED` (default), `ORIGINAL` (no redaction), or `NONE` (omit configs entirely).
 * Since Kyuubi 1.12, `GET /api/v1/sessions` returns only sessions owned by the authenticated user instead of all sessions on the server. To restore the previous behavior, set `kyuubi.frontend.rest.legacy.v1.sessionsReturnAllUsers=true`.
 * Since Kyuubi 1.12, the configuration `spark.sql.kyuubi.hive.connector.dropTableAsPurgeTable` is introduced by Kyuubi Spark Hive connector(KSHC) to control whether DROP TABLE command completely remove its data by skipping HDFS trash. The default value is false. To restore the legacy behavior, set it to true.
+* Since Kyuubi 1.12, the `CHAT` engine is removed.
 
 ## Upgrading from Kyuubi 1.10 to 1.11