Add provider-aware GUI and project demos

[BotondCsereklye]

What changed

• add provider authentication status, model catalogs and intelligence controls to the local GUI
• show active provider details, thinking progress and session-limit failures during runs
• expand provider, security, GUI and configuration documentation
• add reproducible demo media and real screenshots of the running dashboard
• add unit and integration coverage for authentication, catalogs, GUI state and orchestration

Why

Users need clear confirmation that Claude Code and OpenAI Codex are connected, which model each role uses and what the orchestrator is doing during a run.

Validation

• npm run build
• npm run typecheck
• npm run lint
• npm test (52 tests)