Consolidate architecture updates, JS utilities, tests, and agent guidance

[neozhu]

Summary

• add repository guidance for AI coding agents with a new root AGENT.md
• update README.md to reflect the current workflow, EF Core migration command, and superpowers-based planning guidance
• merge broader application and UI updates already present on this branch, including JS utilities, infrastructure wiring, and expanded unit/integration test coverage

What Changed

• documentation and repository guidance
  • add AGENT.md for AI coding agents
  • add docs/superpowers/specs/2026-04-24-agent-md-design.md
  • refresh README.md to remove OpenSpec, recommend superpowers, and update EF Core migration instructions
• solution and runtime composition
  • update solution and project wiring, including Server.UI references and Docker-related files
  • adjust application, infrastructure, and UI integration points across the solution
• application and domain-adjacent code
  • expand constants, interfaces, mappings, exception handling, security, caching, and supporting models
  • refine feature implementations across application modules
• UI and client assets
  • add or update JS interop utilities, routes, navigation, theme assets, and static files
• tests
  • add and revise unit, integration, and infrastructure tests to cover the newer runtime and behavior paths

Commits Included

• dc4412ff Add JS utilities and comprehensive unit/integration tests
• c2edb565 Add Infrastructure project reference to Server.UI
• ea672683 Update README.md to reflect architectural changes and add AGENT.md for AI coding agents

Verification

• not run in this PR creation step

Notes For Reviewers

• this branch is not limited to documentation; it also includes substantial application, UI, infrastructure, and test changes that were already committed before the README/AGENT updates
• the diff versus main is large, so review by commit or by area is recommended
• suggested review order: application/runtime wiring, UI/runtime integration, then documentation

[sonarqubecloud]

Quality Gate failed

Failed conditions
1 Security Hotspot
0.0% Coverage on New Code (required ≥ 80%)
6.4% Duplication on New Code (required ≤ 3%)
E Security Rating on New Code (required ≥ A)
B Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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[github-advanced-security]

CodeQL found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.