feat: consolidate maintenance scripts into packages/internal and add module:new scaffolder

- rename `packages/registry-build` → `packages/internal` to serve as a single home for internal tooling
- add `module-new.ts`: interactive CLI (powered by `@clack/prompts`) that scaffolds a new first-party module under `registry/modules/<slot>-<id>/` with `module.ts`, `package.json`, `tsconfig.json`, `templates/.gitkeep`, and an optional `codemods/index.ts` stub
- expose `pnpm module:new [slot] [id]` at the repo root and update `registry:build` turbo filter to `@stanza/internal`

pnpm-lock.yaml

@@ -130,6 +130,31 @@ importers:
         specifier: ^6.0.3
         version: 6.0.3
 
+  packages/internal:
+    dependencies:
+      '@clack/prompts':
+        specifier: ^1.4.0
+        version: 1.4.0
+      '@stanza/registry':
+        specifier: workspace:*
+        version: link:../registry
+      kleur:
+        specifier: ^4.1.5
+        version: 4.1.5
+      mri:
+        specifier: ^1.2.0
+        version: 1.2.0
+    devDependencies:
+      '@types/bun':
+        specifier: ^1.3.14
+        version: 1.3.14
+      '@types/node':
+        specifier: ^25.9.1
+        version: 25.9.1
+      typescript:
+        specifier: ^6.0.3
+        version: 6.0.3
+
   packages/registry:
     dependencies:
       zod:
@@ -143,22 +168,6 @@ importers:
         specifier: ^4.1.7
         version: 4.1.7(@types/node@25.9.1)(vite@8.0.13(@types/node@25.9.1)(jiti@2.7.0))
 
-  packages/registry-build:
-    dependencies:
-      '@stanza/registry':
-        specifier: workspace:*
-        version: link:../registry
-    devDependencies:
-      '@types/bun':
-        specifier: ^1.3.14
-        version: 1.3.14
-      '@types/node':
-        specifier: ^25.9.1
-        version: 25.9.1
-      typescript:
-        specifier: ^6.0.3
-        version: 6.0.3
-
   registry/modules/auth-better-auth:
     dependencies:
       '@stanza/codemods':