[Application] Restore demo result heatmap fixture

[SilverSupplier]

Summary

• Replace the hollow Evacuation Scenario Demo result with a precomputed blocked-door fixture that carries frame, risk, density, progress, replay, and timing artifacts.
• Remove the app-open synchronous demo simulation loop so the demo result view loads immediately.
• Preserve authoring state through run/result navigation and save/reopen flows.

Related Issue

• Closes Task-데모 결과 화면 히트맵 복구 및 데모 로딩 개선 #202

Area

• Engine
• Domain
• Application
• Docs
• Build
• Analysis
• Chore

Architecture Check

• I kept the dependency direction application -> domain -> engine.
• I did not add Qt UI code to src/domain.
• I did not add domain or application dependencies to src/engine.
• I used src/ as the include root.

Verification

• cmake --preset windows-debug
• cmake --build --preset build-debug --target safecrowd_app
• cmake --build --preset build-debug --target safecrowd_tests
• ctest --preset test-debug
• Not run (reason below)

Risks / Follow-up

• Precomputed demo fixture must be regenerated if simulation logic changes in a way that should alter the built-in demo result.
• Full multi-scenario batch result UI remains out of scope for this hotfix.