Bump javadoc plugin source level to Java 17

The maven-javadoc-plugin had <source>11</source> in both the
"javadoc" and "maven-central-release" profiles, while the compiler
targets Java 17. This mismatch caused javadoc generation to fail on
Java 17 syntax such as switch expressions with arrow labels.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mtopolnik

core/pom.xml

@@ -198,7 +198,7 @@
                         </executions>
                         <configuration>
                             <doclint>none</doclint>
-                            <source>11</source>
+                            <source>17</source>
                             <detectJavaApiLink>false</detectJavaApiLink>
                             <additionalJOptions>
                                 <additionalJOption>${compilerArg1}</additionalJOption>
@@ -296,7 +296,7 @@
                         </executions>
                         <configuration>
                             <doclint>none</doclint>
-                            <source>11</source>
+                            <source>17</source>
                             <detectJavaApiLink>false</detectJavaApiLink>
                             <additionalJOptions>
                                 <additionalJOption>${compilerArg1}</additionalJOption>