Add celestial body exploration missions for starships

[Copilot]

Adds mission system allowing starships to explore 8 Saturn moons (Titan, Enceladus, Rhea, Iapetus, Dione, Tethys, Mimas, Hyperion). Each mission requires specific ships/research level, takes 1-3 days, and grants metal, unstable elements, and permanent bonuses.

Implementation

Mission mechanics

• Validates requirements: ship count, exploration research level, not already explored/in-progress
• Tracks active missions with start/completion days
• Ships occupied during missions (unavailable for other use)
• Auto-completes on day counter tick via checkMissionCompletion()

Reward system

• Immediate: 500-1500 metal, 0-150 unstable elements
• Permanent: +5-15% production or exploration effectiveness
• Bonuses merge into activeRewards.productionBonus / explorationBonus

UI integration

• New celestial bodies panel (visible when ships > 0)
• Status indicators: Unexplored / In Progress (%) / Explored
• Grid layout with launch buttons, requirement validation

State management

• Added exploredBodies: string[] and activeMissions: Mission[] to game state
• Backward compatible: initializes empty arrays for old saves
• Persists across save/load

const celestialBodies = [
  {
    id: 'titan',
    name: 'Titan',
    distance: 1, // days
    requiredShips: 1,
    requiredExplorationLevel: 0,
    rewards: {
      metal: 500,
      bonus: { type: 'production', value: 0.05 }
    }
  },
  // ... 7 more moons
];

Screenshots

Exploration panel with mission status

Completed mission with rewards applied

Files Modified

• game.js: Mission functions, celestial body definitions, UI updates, game loop integration
• index.html: New exploration section
• style.css: Panel styling with grid layout, status indicators
• test_exploration_system.html: Integration test suite (37 tests)

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[sonarqubecloud]

Quality Gate passed

Issues
8 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