ci(codeql): Reduce duplicate scan noise

Remove the Java/Kotlin scan from CodeQL because this repository does not
contain a buildable Java project. Load a dedicated CodeQL config that
excludes generated plugin mirrors so duplicate template classes do not
reduce scan coverage or signal quality.

.github/codeql/codeql-config.yml

@@ -0,0 +1,6 @@
+name: "CodeQL Config"
+
+paths-ignore:
+  # Generated plugin mirrors create duplicate scan noise without adding
+  # source coverage because the canonical sources live outside plugins/.
+  - "plugins/**"

.github/workflows/codeql.yml

@@ -30,8 +30,6 @@ jobs:
             build-mode: none
           - language: go
             build-mode: autobuild
-          - language: java-kotlin
-            build-mode: none
           - language: javascript-typescript
             build-mode: none
           - language: python
@@ -46,6 +44,7 @@ jobs:
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
+          config-file: ./.github/codeql/codeql-config.yml
 
       - name: Autobuild
         if: matrix.build-mode == 'autobuild'