fix: use CLJ_CONFIG for Maven local repo in GraalVM native image

bb is a GraalVM native image — JAVA_TOOL_OPTIONS and CLJ_JVM_OPTS
have no effect. tools.deps (compiled into bb) uses user.home to
find .m2/repository, which resolves to /root inside the awf sandbox.

Fix: write a deps.edn with :mvn/local-repo into ~/.deps.clj/ (already
mounted) and set CLJ_CONFIG to that directory. tools.deps reads
CLJ_CONFIG for user config and finds the :mvn/local-repo override.

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

Author: krukow

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

@@ -70,10 +70,16 @@ jobs:
           fi
           # Inside the awf sandbox $HOME is /root, but the mounts map
           # /home/runner/.deps.clj and /home/runner/.m2 into the container
-          # at those same absolute paths. Set env vars so bb's deps.clj
-          # and the tools JVM use the absolute host paths instead of $HOME.
+          # at those same absolute paths. bb is a GraalVM native image so
+          # JAVA_TOOL_OPTIONS has no effect — we must use env vars that
+          # bb/tools.deps read directly.
+          #
+          # DEPS_CLJ_TOOLS_DIR: tells bb's deps.clj where the tools jar is
+          # CLJ_CONFIG: tells tools.deps where to find user deps.edn (which
+          #   contains :mvn/local-repo pointing to the mounted Maven cache)
+          echo '{:mvn/local-repo "/home/runner/.m2/repository"}' > "$HOME/.deps.clj/deps.edn"
           echo "DEPS_CLJ_TOOLS_DIR=$HOME/.deps.clj" >> "$GITHUB_ENV"
-          echo "JAVA_TOOL_OPTIONS=-Duser.home=$HOME" >> "$GITHUB_ENV"
+          echo "CLJ_CONFIG=$HOME/.deps.clj" >> "$GITHUB_ENV"
           # Ensure deps directories are readable by any user
           chmod -R a+rX ~/.m2/repository ~/.deps.clj 2>/dev/null || true
       - name: Install gh-aw extension