Add mission controllers and register prefabs for AsteroidMining, CriticalDemolition, HazardNeutralization

[jackandcarter]

Motivation

• Provide concrete mission controller implementations for mission types that were defined but missing runtime controllers so MissionLoader can instantiate mission logic.
• Ensure mission HUD modules receive live updates from their matching controllers so UI reflects gameplay state.
• Make controller prefabs discoverable at runtime by registering them in a MissionRegistry asset.

Description

• Added AsteroidMiningMissionController, CriticalDemolitionMissionController, and HazardNeutralizationMissionController under Assets/Missions/*/Scripts, each implementing IMissionController (StartMission, UpdateMission, FinishMission, GetUIRequirements).
• Created controller prefabs under Assets/Missions/*/Prefabs and a MissionRegistry asset at Assets/Missions/MissionRegistry.asset that maps MissionType entries to the new controller prefabs so MissionLoader can resolve them.
• Updated the editor generator spec in Assets/Editor/MissionUIGeneratorWindow.cs to reference the new controller types and to bind the controller HUD field to missionHud for each added mission type.
• Controllers bind to their HUD modules (via the missionHud field) and update UI fields (e.g., time, hazards, ore/targets) as mission state changes.

Testing

• No automated tests were run for these changes.

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Codex Task