fix(docs): type-check the docs app with next typegen, and delete the dead types:check (#10879)

`apps/docs` declared two near-identical type-check scripts:

    "types:check": "fumadocs-mdx && next typegen && tsc --noEmit"
    "typecheck":   "tsc --noEmit"

`types:check` -- the thorough one -- was invoked by nothing (`git grep`
over `.github/`, `scripts/`, `turbo.json` and the root `package.json`
returns only its own declaration). The one CI actually runs is
`typecheck`, reached through `turbo run typecheck --filter='./apps/*'`.

That mattered because `tsconfig.json` includes `.next/types/**/*.ts`,
which only `next typegen` produces. So the program CI type-checked was
set by whether some earlier, unrelated command had populated `.next` --
and on a fresh checkout it had not. Measured with `.next` deleted, the
bare script exits 0 while compiling none of the generated route types.

Wiring the thorough command under the name CI already runs makes the
check a function of source: it generates `.next/types/**` and
`next-env.d.ts` itself before tsc reads them, and short-circuits loudly
if typegen fails. Typegen costs ~1s and needs no build.

Measured coverage delta (empty `.next`, `tsc --listFiles`): 1225 -> 1231
files. The six are `.next/types/validator.ts` (160 lines validating 13
route entry points), `routes.d.ts`, `root-params.d.ts`,
`cache-life.d.ts`, `next-env.d.ts` and, through it,
`next/image-types/global.d.ts` -- so the bare run was also type-checking
a Next app without Next's own ambient declarations.

Ablation, to show the added coverage is real: giving
`app/[lang]/docs/layout.tsx` a `params` shape the route cannot supply
leaves the old script green (exit 0, 0 errors) and makes the new one
fail with TS2344 at `.next/types/validator.ts`, naming the layout and
the missing param.

`include` is deliberately left alone. Next writes both `.next` globs
itself and re-adds either one on the next `next dev` / `next build`;
running `writeConfigurationDefaults` against a narrowed copy put the
`dev` glob straight back and rewrote the file. The rationale is recorded
in `tsconfig.json` where the next reader would try to tidy it.


Claude-Session: https://claude.ai/code/session_01DdCnBGcHeufjrq7drTD3wt

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-zhuang

apps/docs/package.json

@@ -9,9 +9,8 @@
     "build": "pnpm --filter @objectstack/spec gen:schema && pnpm --filter @objectstack/spec gen:docs && NODE_OPTIONS='--max-old-space-size=4096' next build",
     "start": "next start",
     "site:lint": "next lint",
-    "types:check": "fumadocs-mdx && next typegen && tsc --noEmit",
     "postinstall": "fumadocs-mdx",
-    "typecheck": "tsc --noEmit"
+    "typecheck": "fumadocs-mdx && next typegen && tsc --noEmit"
   },
   "dependencies": {
     "fumadocs-core": "16.14.4",

apps/docs/tsconfig.json

@@ -34,6 +34,30 @@
       ]
     }
   },
+  // `typecheck` runs `next typegen` before tsc on purpose, and these two
+  // `.next` globs are why. Next writes both of them itself
+  // (`writeConfigurationDefaults`) and re-adds either one on the next
+  // `next dev` / `next build` if you delete it -- measured by running that
+  // routine against a narrowed copy of this file: the `dev` glob came
+  // straight back and the file was rewritten. This array cannot be narrowed,
+  // so the honesty has to come from the script instead.
+  //
+  //   .next/types/**     produced by the `next typegen` that the `typecheck`
+  //                      script now runs itself, so the checked program is a
+  //                      function of source rather than of whatever `.next` an
+  //                      earlier build happened to leave behind. A bare
+  //                      `tsc --noEmit` here passed over a broken route
+  //                      signature precisely because these files were absent.
+  //   .next/dev/types/** written only by `next dev`. Next's own build-mode
+  //                      type check filters this directory OUT of the program
+  //                      (`getDevTypesPath`, lib/typescript/runTypeCheck.js)
+  //                      "to prevent stale dev types from causing errors when
+  //                      routes have been deleted since the last dev session".
+  //                      Plain tsc has no such filter, so a leftover dev
+  //                      session can only add a local false RED here, never a
+  //                      false green. Remedy: `rm -rf apps/docs/.next`.
+  //
+  // Do not reduce `typecheck` back to a bare `tsc --noEmit`.
   "include": [
     "next-env.d.ts",
     "**/*.ts",