chore(repo): restore the root typecheck script and extend it over stories

The root `typecheck` script (tsc against tsconfig.storybook.json) was
lost in the reset to v1.4.8, leaving packages/*/stories with NO type
checking at all — the per-package tsconfigs include only src/, Storybook
transpiles without checking, and the vitest storybook project runs
pre-built stories. A rename of any src symbol deep-imported by a story
(e.g. devStageTimings' STAGE_MEASURE_PREFIX, consumed by the streaming
profiler) would pass every gate and only surface as a silently-empty
panel at runtime.

Restored and extended: the new tsconfig.storybook.json covers
.storybook/, packages/*/stories (which the pre-reset version never
included), and packages/*/src/typings so the shim declarations
(remark-pangu et al.) resolve for the transitively-checked src imports.

Author: AIEPhoenix

package.json

@@ -8,6 +8,7 @@
     "build": "pnpm --filter './packages/*' run build",
     "lint": "eslint .",
     "lint:fix": "eslint . --fix",
+    "typecheck": "tsc --noEmit -p tsconfig.storybook.json",
     "format": "prettier --write .",
     "format:check": "prettier --check .",
     "version-packages": "node scripts/version-packages.mjs",

tsconfig.storybook.json

@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.base.json",
+  "include": [
+    ".storybook",
+    "packages/*/stories",
+    "packages/*/src/typings",
+    "vitest.config.ts",
+    "vitest.shims.d.ts"
+  ]
+}