feat(url): implement URLPattern API (#25168)

## Summary

Implements the [URLPattern Web
API](https://developer.mozilla.org/en-US/docs/Web/API/URLPattern) based
on WebKit's implementation. URLPattern provides declarative pattern
matching for URLs, similar to how regular expressions work for strings.

### Features

- **Constructor**: Create patterns from strings or `URLPatternInit`
dictionaries
- **`test()`**: Check if a URL matches the pattern (returns boolean)
- **`exec()`**: Extract matched groups from a URL (returns
`URLPatternResult` or null)
- **Pattern properties**: `protocol`, `username`, `password`,
`hostname`, `port`, `pathname`, `search`, `hash`
- **`hasRegExpGroups`**: Detect if the pattern uses custom regular
expressions

### Example Usage

```js
// Match URLs with a user ID parameter
const pattern = new URLPattern({ pathname: '/users/:id' });

pattern.test('https://example.com/users/123'); // true
pattern.test('https://example.com/posts/456'); // false

const result = pattern.exec('https://example.com/users/123');
console.log(result.pathname.groups.id); // "123"

// Wildcard matching
const filesPattern = new URLPattern({ pathname: '/files/*' });
const match = filesPattern.exec('https://example.com/files/image.png');
console.log(match.pathname.groups[0]); // "image.png"
```

## Implementation Notes

- Adapted from WebKit's URLPattern implementation
- Modified JS bindings to work with Bun's infrastructure (simpler
`convertDictionary` patterns, WTF::Variant handling)
- Added IsoSubspaces for proper GC integration

## Test Plan

- [x] 408 tests from Web Platform Tests pass
- [x] Tests fail with system Bun (URLPattern not defined), pass with
debug build
- [x] Manual testing of basic functionality

Fixes https://github.com/oven-sh/bun/issues/2286

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

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

src/bun.js/bindings/webcore/JSURLPatternOptions.cpp

@@ -0,0 +1,56 @@
+/*
+    This file is part of the WebKit open source project.
+    This file has been generated by generate-bindings.pl. DO NOT MODIFY!
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#include "config.h"
+#include "JSURLPatternOptions.h"
+
+#include "JSDOMConvertBoolean.h"
+#include <JavaScriptCore/JSCInlines.h>
+
+namespace WebCore {
+using namespace JSC;
+
+template<> URLPatternOptions convertDictionary<URLPatternOptions>(JSGlobalObject& lexicalGlobalObject, JSValue value)
+{
+    auto& vm = JSC::getVM(&lexicalGlobalObject);
+    auto throwScope = DECLARE_THROW_SCOPE(vm);
+    bool isNullOrUndefined = value.isUndefinedOrNull();
+    auto* object = isNullOrUndefined ? nullptr : value.getObject();
+    if (!isNullOrUndefined && !object) [[unlikely]] {
+        throwTypeError(&lexicalGlobalObject, throwScope);
+        return {};
+    }
+    URLPatternOptions result;
+    JSValue ignoreCaseValue;
+    if (isNullOrUndefined)
+        ignoreCaseValue = jsUndefined();
+    else {
+        ignoreCaseValue = object->get(&lexicalGlobalObject, Identifier::fromString(vm, "ignoreCase"_s));
+        RETURN_IF_EXCEPTION(throwScope, {});
+    }
+    if (!ignoreCaseValue.isUndefined()) {
+        result.ignoreCase = convert<IDLBoolean>(lexicalGlobalObject, ignoreCaseValue);
+        RETURN_IF_EXCEPTION(throwScope, {});
+    } else
+        result.ignoreCase = false;
+    return result;
+}
+
+} // namespace WebCore