Add commit hash to footer for deployment verification

- Display git commit hash in footer to track deployed version
- Create cross-platform build script to inject commit hash
- Update build process to include version information

🤖 Generated with [Claude Code](https://claude.ai/code)

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

package-lock.json

@@ -58,6 +58,7 @@
         "@types/react-dom": "^18",
         "aws-cdk-lib": "^2.189.1",
         "constructs": "^10.4.2",
+        "cross-env": "^7.0.3",
         "esbuild": "^0.25.5",
         "eslint": "^9.30.0",
         "eslint-config-next": "15.3.4",
@@ -5633,6 +5634,25 @@
         "node": ">= 0.10"
       }
     },
+    "node_modules/cross-env": {
+      "version": "7.0.3",
+      "resolved": "https://registry.npmjs.org/cross-env/-/cross-env-7.0.3.tgz",
+      "integrity": "sha512-+/HKd6EgcQCJGh2PSjZuUitQBQynKor4wrFbRg4DtAgS1aWO+gU52xpH7M9ScGgXSYmAVS9bIJ8EzuaGw0oNAw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "cross-spawn": "^7.0.1"
+      },
+      "bin": {
+        "cross-env": "src/bin/cross-env.js",
+        "cross-env-shell": "src/bin/cross-env-shell.js"
+      },
+      "engines": {
+        "node": ">=10.14",
+        "npm": ">=6",
+        "yarn": ">=1"
+      }
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.6",
       "license": "MIT",