Add Civ Lite resources and trade

[YfengJ]

Summary

• add a deterministic Civ Lite resource model for strategic and luxury resources
• connect controlled resource yields into city resource gathering and visible map/minimap/tooltips
• add a Resources & Trade sidebar with a finite trade-route action between player and bot empires

Closes #20

Validation

• node --test demo/civ-lite/resource-model.test.mjs
• node --check demo/civ-lite/resource-model.js
• node --check demo/civ-lite/game.js
• node --check demo/civ-lite/sprites.js
• git diff --check
• Playwright CLI smoke on http://127.0.0.1:4202/demo/civ-lite/: sidebar resources rendered, trade route opened, end turn updated food/prod/science and trade duration, canvas pixel sample was non-empty. Only favicon.ico 404 appeared in console.

[YfengJ]

CI note: the failing Build Godot Web export job is still stopping at the existing Godot Web preset configuration error: Cannot export project with preset Web due to configuration errors. This PR only changes demo/civ-lite JS/HTML/CSS plus a local resource-model test. Local validation passed: node --test demo/civ-lite/resource-model.test.mjs; node --check demo/civ-lite/resource-model.js; node --check demo/civ-lite/game.js; node --check demo/civ-lite/sprites.js; git diff --check; and a Playwright CLI smoke check for resource/trade panel rendering, opening a trade route, end-turn resource updates, active trade duration, and non-empty canvas rendering. SonarCloud Quality Gate passes with 0 new issues on latest head 4ba9738.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud