chore: add CI workflow (typecheck + prettier format check), tsconfig, and prettier formatting

package-lock.json

@@ -14,6 +14,7 @@
       "devDependencies": {
         "@mariozechner/pi-coding-agent": "0.72.0",
         "@types/node": "25.6.0",
+        "prettier": "^3.5.0",
         "tsx": "4.21.0",
         "typescript": "6.0.3"
       }
@@ -3621,6 +3622,22 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/prettier": {
+      "version": "3.8.3",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-3.8.3.tgz",
+      "integrity": "sha512-7igPTM53cGHMW8xWuVTydi2KO233VFiTNyF5hLJqpilHfmn8C8gPf+PS7dUT64YcXFbiMGZxS9pCSxL/Dxm/Jw==",
+      "dev": true,
+      "license": "MIT",
+      "bin": {
+        "prettier": "bin/prettier.cjs"
+      },
+      "engines": {
+        "node": ">=14"
+      },
+      "funding": {
+        "url": "https://github.com/prettier/prettier?sponsor=1"
+      }
+    },
     "node_modules/proper-lockfile": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/proper-lockfile/-/proper-lockfile-4.1.2.tgz",