feat: add Bun.JSONL.parse() for streaming newline-delimited JSON parsing (#26356)

Adds a built-in JSONL parser implemented in C++ using JavaScriptCore's
optimized JSON parser.

## API

### `Bun.JSONL.parse(input)`
Parse a complete JSONL string or `Uint8Array` and return an array of all
parsed values. Throws on invalid input.

```ts
const results = Bun.JSONL.parse('{"a":1}\n{"b":2}\n');
// [{ a: 1 }, { b: 2 }]
```

### `Bun.JSONL.parseChunk(input, start?, end?)`
Parse as many complete values as possible, returning `{ values, read,
done, error }`. Designed for streaming use cases where input arrives
incrementally.

```ts
const result = Bun.JSONL.parseChunk('{"id":1}\n{"id":2}\n{"id":3');
result.values; // [{ id: 1 }, { id: 2 }]
result.read;   // 17
result.done;   // false
result.error;  // null
```

## Implementation Details

- C++ implementation in `BunObject.cpp` using JSC's `streamingJSONParse`
- ASCII fast path: zero-copy `StringView` for pure ASCII input
- Non-ASCII: uses `fromUTF8ReplacingInvalidSequences` with
`utf16_length_from_utf8` size check to prevent overflow
- UTF-8 BOM automatically skipped for `Uint8Array` input
- Pre-built `Structure` with fixed property offsets for fast result
object creation
- `Symbol.toStringTag = "JSONL"` on the namespace object
- `parseChunk` returns errors in `error` property instead of throwing,
preserving partial results
- Comprehensive boundary checks on start/end parameters

## Tests

234 tests covering:
- Complete and partial/streaming input scenarios
- Error handling and recovery
- UTF-8 multi-byte characters and BOM handling
- start/end boundary security (exhaustive combinations, clamping, OOB
prevention)
- 4 GB input rejection (both ASCII and non-ASCII paths)
- Edge cases (empty input, single values, whitespace, special numbers)

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

test/js/bun/css/doesnt_crash.test.ts

@@ -25,15 +25,22 @@ describe("doesnt_crash", async () => {
       { target: "browser", minify: false },
       { target: "browser", minify: true },
     ];
+    let code = "";
+    async function getCode() {
+      if (code) return code;
+      code = await Bun.file(absolute).text();
+      return code;
+    }
 
     for (const { target, minify } of configs) {
-      test(`${file} - ${minify ? "minify" : "not minify"}`, async () => {
+      test(`${file} - ${minify ? "minify" : "not minify"} - ${target}`, async () => {
         const timeLog = `Transpiled ${file} - ${minify ? "minify" : "not minify"}`;
         console.time(timeLog);
         const { logs, outputs } = await Bun.build({
           entrypoints: [absolute],
           minify: minify,
           target,
+          files: { [absolute]: await getCode() },
         });
         console.timeEnd(timeLog);
 
@@ -43,6 +50,7 @@ describe("doesnt_crash", async () => {
 
         expect(outputs.length).toBe(1);
         const outfile1 = path.join(temp_dir, "file-1" + file).replaceAll("\\", "/");
+        const content1 = await outputs[0].text();
 
         await Bun.write(outfile1, outputs[0]);
 
@@ -53,6 +61,7 @@ describe("doesnt_crash", async () => {
           const { logs, outputs } = await Bun.build({
             entrypoints: [outfile1],
             target,
+            files: { [outfile1]: content1 },
             minify: minify,
           });
 

test/no-validate-exceptions.txt

@@ -157,4 +157,7 @@ vendor/elysia/test/ws/message.test.ts
 test/js/node/test/parallel/test-worker-abort-on-uncaught-exception.js
 
 # TODO: WebCore fixes
-test/js/web/urlpattern/urlpattern.test.ts
+test/js/web/urlpattern/urlpattern.test.ts
+
+# TODO: jsc
+test/js/bun/jsonl/jsonl-parse.test.ts