Add Civ Lite technology tree gameplay

[YfengJ]

Summary

• add a compact Civ-style technology tree model with prerequisites, science costs, unlocks, research statuses, and deterministic bot technology choice
• wire the player and bot turn loops so science income advances current research and completed tech unlocks stronger trainable units
• add a Technology sidebar panel with researched / available / blocked / in-progress states and selectable research buttons
• add focused node:test coverage for tech prerequisites, research progress, unlocks, bot choices, and markup

Closes #15

Notes

• scoped to demo/civ-lite/* gameplay and UI
• does not touch wallet, payment, identity, API-key, or Web3 reward flows

Validation

• node --test demo/civ-lite/tech-model.test.mjs
• node --check demo/civ-lite/game.js && node --check demo/civ-lite/sprites.js && node --check demo/civ-lite/tech-model.js
• git diff --cached --check
• Playwright smoke test on http://127.0.0.1:4195/demo/civ-lite/: Technology panel rendered, Archery selection updated current research, canvas pixel sample was non-empty

[YfengJ]

CI note: the Godot Web build failure appears unrelated to this tech-tree PR. This branch only changes demo/civ-lite/*, while upstream main is already failing the same workflow at b86ad79 with Cannot export project with preset "Web" due to configuration errors in make godot-export.

Local validation for this PR passed:

• node --test demo/civ-lite/tech-model.test.mjs
• node --check demo/civ-lite/game.js && node --check demo/civ-lite/sprites.js && node --check demo/civ-lite/tech-model.js
• git diff --cached --check
• Playwright smoke test: technology panel rendered, Archery selection updated current research, and the canvas pixel sample was non-empty.

[sonarqubecloud]

Quality Gate passed

Issues
2 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