Add Civ Lite production queue and victory loops

[YfengJ]

Closes #16.

Summary

• Adds a tested Civ Lite production model for city queues, overflow progress, movement planning, and conquest/domination victory evaluation.
• Wires Athens/Babylon into production queues, completed unit spawning, movement-cost planning, city capture checks, and victory state updates.
• Adds a city production panel with Warrior/Scout queue actions, progress display, and queue status.

Validation

• node --test demo/civ-lite/production-model.test.mjs
• node --check demo/civ-lite/production-model.js
• node --check demo/civ-lite/game.js
• node --check demo/civ-lite/sprites.js
• git diff --check
• Browser smoke: opened demo/civ-lite/index.html, queued Scout, ended a turn, verified Warrior completion, Scout progress, nonblank canvas, and 0 console errors after reload.

This only touches the Civ Lite gameplay demo; it does not modify wallet, Web3, payout, identity, or reward flows.

[YfengJ]

CI note: SonarCloud passed. The Build Godot Web export job fails at the existing Godot export step with Cannot export project with preset "Web" due to configuration errors while running make godot-export. This PR only changes the Civ Lite demo JS/HTML/CSS and does not touch the Godot export preset or workflow.

Local validation for the changed demo passed:

• node --test demo/civ-lite/production-model.test.mjs
• node --check demo/civ-lite/production-model.js
• node --check demo/civ-lite/game.js
• node --check demo/civ-lite/sprites.js
• git diff --check
• Browser smoke: queued Scout, ended a turn, confirmed Warrior completion / Scout queue state, nonblank canvas, and no console errors after reload.

[sonarqubecloud]

Quality Gate passed

Issues
3 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