👷 Type-check the TS floor in CI

Add a `compat` job that type-checks the whole suite and a consumer fixture
against the minimum supported TypeScript (5.9), reusing the `dist/` artifact
`build` produced and gating `publish`. The compiler is resolved by npx, so it
never enters `devDependencies` or the local `check`/`verify` loop.

The fixture imports the package by name, resolving the emitted declarations
through the `exports` map; `expectTypeOf` / `.not.toBeAny()` make it reject an
`any`-typed declaration, which a bare compile would accept.

Correct the README consumer floor from >= 5.0 to >= 5.9 (set by `type-fest`)
and drop the `node10` resolution claim, which the exports-only entry never
satisfied.

README.md

@@ -54,9 +54,14 @@ npm install tiny-pattern-ts
 ## Requirements
 
 - **Node.js >= 26** (`engines` field; pinned via `.node-version`).
-- **TypeScript >= 5.0** to consume the published declarations. The emitted `.d.ts`
-  use `const` type parameters (TS 5.0) and keep their relative `.ts` specifiers;
-  both resolve on TS >= 5.0 in `node10` / `node16` / `nodenext` / `bundler`.
+- **TypeScript >= 5.9** to consume the published declarations. The floor is set
+  by the `type-fest` types the declarations use and is checked in CI against a
+  consumer fixture; see [`compat/`](./compat) and
+  [development/ci.md § TypeScript compatibility](./development/ci.md#typescript-compatibility).
+  The emitted `.d.ts` keep their relative `.ts` specifiers, which resolve under
+  `node16` / `nodenext` / `bundler`. The package exposes only an `exports` map
+  (no `main` / top-level `types`), so the legacy `node10` resolver does not
+  apply.
 - The package is **ESM-only** (no CommonJS shim).
 
 ## Examples