chore: remove obsolete markdown-it 14 typings after v15 migration

SCARP-DOCS-ENGINE.md

@@ -16,7 +16,7 @@ The new engine lives in scripts/scarp-site/ and loads no VitePress or Vue websit
 | test.ts | Static route, Unicode, SEO, markup, search and release-evidence tests |
 | browser-test.ts | Real Chromium keyboard, mobile, search, Command Finder and axe WCAG A/AA tests |
 
-The build uses focused Markdown (markdown-it) and YAML (yaml) parsers, not a website framework. The browser code is standalone TypeScript compiled with TypeScript itself, without a JavaScript UI framework or bundler. Release command data now lives in the framework-neutral `scripts/lib/command-finder.ts` module used directly by the Scarp-owned renderer, browser tests and release validators. The old theme-tree import is a one-line compatibility export only for the historical Vue demo; it can be removed alongside the other legacy theme/config files after the remaining migration gates pass.
+The build uses focused Markdown (markdown-it 15 with its own TypeScript declarations) and YAML (yaml) parsers, not a website framework. The obsolete `@types/markdown-it` 14.x package is intentionally excluded and rejected by toolchain policy to prevent split parser types. The browser code is standalone TypeScript compiled with TypeScript itself, without a JavaScript UI framework or bundler. Release command data now lives in the framework-neutral `scripts/lib/command-finder.ts` module used directly by the Scarp-owned renderer, browser tests and release validators. The old theme-tree import is a one-line compatibility export only for the historical Vue demo; it can be removed alongside the other legacy theme/config files after the remaining migration gates pass.
 
 ## Commands
 

package.json

@@ -104,7 +104,6 @@
     "playwright": "1.64.1",
     "axe-core": "4.14.0",
     "markdown-it": "15.0.3",
-    "@types/markdown-it": "14.1.2",
     "yaml": "2.9.1"
   },
   "engines": {

scripts/lib/toolchain-policy.ts

@@ -28,6 +28,13 @@ export function validateToolchain(pkg: ToolchainPackage, dependabotYaml: string)
       errors.push(dependency + ' must be an explicitly pinned source-parsing dependency')
     }
   }
+  // markdown-it 15+ ships its own declarations. Stale DefinitelyTyped 14.x
+  // declarations would introduce duplicate, version-mismatched interfaces.
+  const parser = deps['markdown-it']
+  const parserMajor = typeof parser === 'string' ? Number.parseInt(parser.split('.')[0] ?? '', 10) : NaN
+  if (parserMajor >= 15 && '@types/markdown-it' in deps) {
+    errors.push('markdown-it 15+ bundles its own types: remove obsolete @types/markdown-it')
+  }
   for (const removed of ['vitepress','vue-tsc']) {
     if (removed in deps) errors.push('Removed framework/checker dependency must not return: ' + removed)
   }

scripts/test-toolchain.ts

@@ -35,6 +35,9 @@ for (const [name, changed] of [
 ] as const) {
   mustFail(name,mutatePackage({devDependencies:changed}))
 }
+mustFail('obsolete markdown-it type package',mutatePackage({
+  devDependencies:{'@types/markdown-it':'14.1.2'}
+}),yaml,'@types/markdown-it')
 mustFail('missing Markdown parser',mutatePackage({
   devDependencies:{'markdown-it':undefined}
 }),yaml,'markdown-it')