✅ Assert README example results

Assign every documented matcher result to a variable and assert it with
`assert.equal`, so the compiled README doc-tests verify behavior instead
of merely running the code. The examples import `node:assert` themselves
to stay copy-pasteable; the generator now merges that import into its
prelude assert rather than rejecting it (only `node:test` remains
reserved).

development/docs.md

@@ -38,8 +38,9 @@ Compile every `ts / `typescript fence in the prose docs into a real
   `docs/` + `examples/` list is the natural extension; `development/` must never
   be scanned (its fences are illustrative, not compilable).
 - The generator hoists and merges leading imports, rewrites `tiny-pattern-ts` to
-  the `#test-tiny-pattern-ts` source alias, and rejects an example that imports
-  `node:assert` / `node:test` (the prelude already binds both). Titles are the
+  the `#test-tiny-pattern-ts` source alias, merges an example's `node:assert`
+  import into the prelude assert, and rejects an example that imports
+  `node:test` (the prelude binds `test`). Titles are the
   immediately preceding paragraph; a fence with no such paragraph is a fatal
   error, which keeps every example described.
 - `oxlint src/doc-test` reports "No files found" because the generated