bootstrap repo to mosaic standards layer

scripts/agent/common.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root() {
+  git rev-parse --show-toplevel 2>/dev/null || pwd
+}
+
+ensure_repo_root() {
+  cd "$(repo_root)"
+}
+
+has_remote() {
+  git remote get-url origin >/dev/null 2>&1
+}
+
+run_step() {
+  local label="$1"
+  shift
+  echo "[agent-framework] $label"
+  "$@"
+}
+
+load_repo_hooks() {
+  local hooks_file=".mosaic/repo-hooks.sh"
+  if [[ -f "$hooks_file" ]]; then
+    # shellcheck disable=SC1090
+    source "$hooks_file"
+  fi
+}