Add Java/Clojure/bb setup to copilot-setup-steps

Add Java 21, Clojure CLI, Babashka, and dependency caching
to the Copilot Agent environment (mirrors ci.yml setup).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: krukow

.github/workflows/copilot-setup-steps.yml

@@ -19,7 +19,26 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
+      - uses: actions/setup-java@v5
+        with:
+          distribution: 'temurin'
+          java-version: '21'
+      - name: Set up Clojure
+        uses: DeLaGuardo/setup-clojure@13.5.2
+        with:
+          cli: latest
+          bb: 1.12.214
+      - name: Cache Clojure deps
+        uses: actions/cache@v5
+        with:
+          path: |
+            ~/.m2/repository
+            ~/.gitlibs
+            ~/.deps.clj
+            .cpcache
+          key: cljdeps-${{ hashFiles('deps.edn', 'bb.edn') }}
+          restore-keys: cljdeps-
       - name: Install gh-aw extension
         uses: github/gh-aw/actions/setup-cli@v0.46.0
         with: