Create GitHub Copilot instructions

[replakcan]

Description

Create repository-level AI instructions so AI-assisted tools understand the project goals, architecture, and constraints.

Scope

• Add .github/copilot-instructions.md
• Document project goal
• Document tech stack
• Document static export constraints
• Document code style expectations
• Document review focus

Out of Scope

• Installing or configuring paid AI tools
• Creating custom GitHub Actions AI bot
• Writing implementation code

Acceptance Criteria

• .github/copilot-instructions.md exists
• Project goal is documented
• Tech stack is documented
• Static export constraints are documented
• Code style expectations are documented
• Review focus is documented

Technical Notes

• AI reviewers should be instructed not to suggest server-only features.
• AI reviewers should prioritize static export compatibility.

Related

• Related to: Create PR review guidelines document