docs: update benchmarks and contributor guidelines

[suckserberg]

Summary

Updates technical documentation to reflect the new security hardening features and latest benchmark results. Also introduces a contributor change checklist to maintain code quality.

Technical Implementation

• CHANGELOG: Added version 0.1.2 notes and restored history for 0.1.1/0.1.0.
• Benchmarks: Updated with results from the v0.1.2 stress tests.
• Guides: Added "Listener Protection" and "Bounds Checking" sections to security.md. Added a "Change Checklist" to development-patterns.md.
• API Docs: Documented initialization safety and error isolation behavior.

Changelog Entry

• [Docs]: Updated benchmarks, security guides, and added contributor checklists.

Type of Change

• Feature
• Bug Fix
• Performance Optimization
• Documentation Update
• Maintenance / Chore

Verification and Standards

• I have adhered to the Development Patterns.
• I have verified that all technical documentation accurately reflects the current API.