Add Object.keys, Object.values, and Object.entries

[memburg]

Goal

Add core static Object utility methods.

Why

These APIs are frequently used for object iteration and data transformation.

Scope

Implement support for:

• Object.keys(obj)
• Object.values(obj)
• Object.entries(obj)

Plan

• Extend global Object with these static methods.
• Return arrays with stable, predictable key order.
• Add specs for plain objects and basic validation behavior.
• Update reference docs.

Out of Scope

• Full descriptor/prototype semantics in first pass.