refactor: extract seed provision scripts to dedicated directory

Move bootstrap, default, and inform scripts from inline template
strings in lib/init.ts to standalone files under seed/, loaded via
an esbuild text-loader plugin. Add type-checking (provisions.d.ts,
tsconfig.json) and ESLint config for the seed scripts. Set tsconfig
module to Preserve to support import attributes.

seed/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "checkJs": true,
+    "noEmit": true,
+    "target": "ES2022",
+    "types": []
+  },
+  "include": ["./*.js", "./*.d.ts"]
+}