feat(course-format): stcourse.yaml schema

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

bun.lock

@@ -29,6 +29,9 @@
     "packages/course-format": {
       "name": "@stc/course-format",
       "version": "0.0.0",
+      "dependencies": {
+        "zod": "^4.6.7",
+      },
     },
     "packages/db": {
       "name": "@stc/db",
@@ -90,6 +93,8 @@
 
     "undici-types": ["undici-types@8.12.3", "", {}, "sha512-EXE4ydL3S76dFb27UFjNVZHTyv/TLdATj/KUe29ptdcg6qXL48J2tZ3126E5kICj5jn781OR+XlVH1N6Mz8jbA=="],
 
+    "zod": ["zod@4.6.7", "", {}, "sha512-g8W2D2kU6a8untc053fX1uVBKzM7yqAxW/3zwk83+6RyF2+SKOuV+c0wBDhUwzV1PaGapmZH+rmcUzPf+3CGwg=="],
+
     "@types/node/undici-types": ["undici-types@8.9.0", "", {}, "sha512-KTDyRTYX8sWmKXAikPHHSyc63CRPETMctyjKFupcC6OBLXT3xsN0e9aF7m+mIXutFWpUXuedtowG7iLOzp0kQg=="],
   }
 }