chore: enforce repository rulesets to protect core architectural integrity

[brucethagwana]

Purpose

As this repository scales, maintaining strict architectural boundaries is critical. To protect our codebase from regression, accidental implementation leaks, or breaking changes, we have deprecated direct pushes to the default branch.

System Context & Risk Mitigation

• Risk: Direct pushes threaten our Interface-Driven Design (AbstractLLMAdapter). Unvetted changes can cause leaky abstractions between the application layer and our future Phase 2 infrastructure (PagedAttention, continuous batching, and quantization testing).
• Protection: Forcing PRs ensures every change is checked against structural compliance (JSON schemas) and semantic constraints before merging.

Changes Implemented

• Implemented GitHub Repository Rulesets to block direct pushes to main/master.
• Enforced strict PR-driven development.
• Adjusted admin bypass configurations to maintain development velocity for the repository owner without sacrificing the PR wrapper.

Action Required

All future work—including minor refactors—must be branched independently and submitted via a Pull Request. Direct terminal pushes will be rejected by GitHub's remote hooks.