fix(docs): make examples runnable as plain JS

Cookbook and README code blocks were labeled \`ts\` but mixed TS-only
syntax (type guards, generics, non-null assertions) into runnable
examples. A user copy-pasting into \`test.mjs\` and running with node
hit SyntaxErrors. Also Recipe 5's generic-alternative block referenced
MAGIC_KINGDOM without declaring it.

- Rename runnable blocks from \`ts\` to \`js\` and strip TS-only syntax.
- Keep the single TypeScript example (Cache adapter with \`implements\`)
  labeled \`ts\` with a note on how to translate.
- Add a preamble in both docs explaining the js vs ts file-extension
  swap so users know which runtime to use.
- Add the missing MAGIC_KINGDOM constant in the generic-alternative
  block.
- Replace \`wdw!.id\` (TS non-null assertion) with a real entity id in
  the low-level escape-hatch example.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: cubehouse

README.md

@@ -14,7 +14,11 @@ Runs on Node 18+, evergreen browsers, Deno, Bun, and Cloudflare Workers. Zero ru
 
 ## Print live wait times
 
-```ts
+Every example in this README works as plain JavaScript — save as `.mjs` and
+run with `node`. To use them as TypeScript, rename to `.ts` and run with
+`npx tsx`; the SDK ships full `.d.ts` types so TypeScript infers everything.
+
+```js
 import { ThemeParks, currentWaitTime } from 'themeparks';
 
 const MAGIC_KINGDOM = '75ea578a-adc8-4116-a54d-dccb60765ef9';
@@ -56,7 +60,7 @@ Jungle Cruise                                      40 min
 
 Example:
 
-```ts
+```js
 const tp = new ThemeParks({
   userAgent: 'my-app/1.2.3 (+https://example.com)',
   timeoutMs: 15_000,
@@ -81,7 +85,7 @@ Each variant is exposed as a key on `entry.queue`. All are optional — `undefin
 
 ### Direct access
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const tp = new ThemeParks();
@@ -116,7 +120,7 @@ for (const entry of live.liveData ?? []) {
 
 If branching on every variant is too verbose, `narrowQueues(queue)` flattens all populated variants into a typed discriminated union:
 
-```ts
+```js
 import { ThemeParks, narrowQueues } from 'themeparks';
 
 const tp = new ThemeParks();
@@ -135,7 +139,7 @@ for (const entry of live.liveData ?? []) {
 
 ## Ergonomic helpers
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const tp = new ThemeParks();
@@ -159,17 +163,17 @@ console.log(`${entries.length} schedule entries`);
 
 Every ergonomic helper is built on top of `tp.raw`, which is a thin, typed 1:1 wrapper over the OpenAPI operations. Use it directly when you want the raw response shape:
 
-```ts
+```js
 const live = await tp.raw.getEntityLive('75ea578a-adc8-4116-a54d-dccb60765ef9');
 const dests = await tp.raw.getDestinations();
-const children = await tp.raw.getEntityChildren(wdw!.id);
+const children = await tp.raw.getEntityChildren('e957da41-3552-4cf6-b636-5babc5cbc4e5');
 ```
 
 ## Error handling
 
 All SDK errors inherit from `ThemeParksError`. The ones you'll typically catch:
 
-```ts
+```js
 import { ThemeParks, ApiError, RateLimitError, NetworkError, TimeoutError } from 'themeparks';
 
 const tp = new ThemeParks();
@@ -196,7 +200,7 @@ try {
 
 There's no built-in HTTP logger to flip on (we run directly on platform `fetch`). The clean idiom is to pass a wrapping `fetch` implementation:
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const tp = new ThemeParks({
@@ -226,13 +230,13 @@ The default client caches `GET` responses in-memory (LRU) with sensible per-endp
 
 ### Disable caching
 
-```ts
+```js
 const tp = new ThemeParks({ cache: false });
 ```
 
 ### Plug in your own adapter
 
-`Cache` is a structural interface — any object implementing `get`, `set`, and `delete` works. Redis, filesystem, IndexedDB, etc.:
+`Cache` is a structural interface — any object implementing `get`, `set`, and `delete` works. Redis, filesystem, IndexedDB, etc. (TypeScript shown; drop the annotations for plain JS):
 
 ```ts
 import { ThemeParks, type Cache } from 'themeparks';

docs/cookbook.md

@@ -8,12 +8,17 @@ Entity IDs used throughout:
 - Magic Kingdom: `75ea578a-adc8-4116-a54d-dccb60765ef9`
 - Walt Disney World Resort: `e957da41-3552-4cf6-b636-5babc5cbc4e5`
 
+Every example below is written as plain JavaScript with ES modules. Save any
+block as `test.mjs` and run it with `node test.mjs` (Node ≥18). For
+TypeScript just rename to `.ts` and run with `npx tsx test.ts` — the SDK
+ships full `.d.ts` types so TypeScript will infer the shapes automatically.
+
 ## Recipe 1 — Wait times in order (longest → shortest)
 
 Pull the live data for Magic Kingdom, keep only the rides that are reporting
 a wait time, and print them sorted from longest to shortest queue.
 
-```ts
+```js
 import { ThemeParks, currentWaitTime } from 'themeparks';
 
 const MAGIC_KINGDOM = '75ea578a-adc8-4116-a54d-dccb60765ef9';
@@ -23,7 +28,7 @@ const live = await tp.entity(MAGIC_KINGDOM).live();
 
 const waits = (live.liveData ?? [])
   .map((entry) => ({ name: entry.name, wait: currentWaitTime(entry) }))
-  .filter((w): w is { name: string; wait: number } => w.wait !== null)
+  .filter((w) => w.wait !== null)
   .sort((a, b) => b.wait - a.wait);
 
 for (const { name, wait } of waits) {
@@ -56,7 +61,7 @@ EXTRA_HOURS (early entry / extended evening), and TICKETED_EVENT (after-hours
 events). `range()` returns them all in chronological order across any month
 boundaries.
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const MAGIC_KINGDOM = '75ea578a-adc8-4116-a54d-dccb60765ef9';
@@ -98,14 +103,14 @@ coordinates by `entityType`:
 > tree in a single response, so even for the largest destinations this is
 > one HTTP request.
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const WALT_DISNEY_WORLD = 'e957da41-3552-4cf6-b636-5babc5cbc4e5';
 
 const tp = new ThemeParks();
 
-const byType = new Map<string, Array<{ name: string; lat: number; lng: number }>>();
+const byType = new Map();
 
 for await (const child of tp.entity(WALT_DISNEY_WORLD).walk()) {
   const loc = child.location;
@@ -154,7 +159,7 @@ RESTAURANT (218)
 There's no built-in HTTP logger to flip on (the SDK runs directly on platform
 `fetch`). The clean idiom is to pass a wrapping `fetch` implementation:
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const tp = new ThemeParks({
@@ -202,7 +207,7 @@ Lane) plus SINGLE_RIDER. The full set of variants is:
 
 Print all populated queue variants for every attraction at Magic Kingdom:
 
-```ts
+```js
 import { ThemeParks } from 'themeparks';
 
 const MAGIC_KINGDOM = '75ea578a-adc8-4116-a54d-dccb60765ef9';
@@ -259,9 +264,11 @@ TRON Lightcycle / Run                     LIGHTNING LANE $20.00, return 2026-04-
 If branching on every variant is too verbose, `narrowQueues(queue)` flattens
 all populated variants into a typed discriminated union you can switch over:
 
-```ts
+```js
 import { ThemeParks, narrowQueues } from 'themeparks';
 
+const MAGIC_KINGDOM = '75ea578a-adc8-4116-a54d-dccb60765ef9';
+
 const tp = new ThemeParks();
 const live = await tp.entity(MAGIC_KINGDOM).live();