Add support for JSDoc @implements tag in reparser

[Copilot]

This PR adds support for the JSDoc @implements tag by implementing the missing case in the reparser to create synthetic heritage clauses.

Problem

The JSDoc @implements tag was already being parsed correctly in jsdoc.go, but the reparser in reparser.go was missing the case to handle KindJSDocImplementsTag. This meant that while the tag was recognized, it wasn't being converted into a synthetic heritage clause that TypeScript tooling could understand.

Solution

Added a case for ast.KindJSDocImplementsTag in the reparseTags function that:

1. Creates synthetic heritage clauses with KindImplementsKeyword token
2. Handles both class declarations and class expressions
3. Preserves type arguments from the JSDoc tag's className
4. Maintains existing heritage clauses when adding new implements clauses
5. Sets appropriate flags for reparsed nodes

Examples

Before this change, JSDoc @implements tags were parsed but ignored:

/**
 * @implements {Foo}
 * @implements {Bar<string>}
 */
class MyClass extends BaseClass {
    // No synthetic heritage clauses created
}

After this change, the reparser creates proper heritage clauses:

/**
 * @implements {Foo}
 * @implements {Bar<string>}
 */
class MyClass extends BaseClass implements Foo, Bar<string> {
    // Synthetic heritage clauses enable proper type checking
}

Testing

• ✅ Single @implements {Foo} creates heritage clause with implements keyword
• ✅ Multiple @implements tags create multiple heritage clauses
• ✅ Generic types like @implements {Bar<T>} handled correctly
• ✅ Works alongside existing extends clauses
• ✅ Supports both class declarations and class expressions
• ✅ All existing parser tests pass
• ✅ Build succeeds

Fixes #1103.

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