Add 5 major features: Template Library, Custom Judges, Spectator Mode, Achievements, and Game History

[Copilot]

Adds comprehensive feature set to enhance gameplay experience and player engagement based on analysis of existing game mechanics.

Core Features

Prompt Template Library

• 12 pre-made templates categorized by style (搞笑, 戲劇, 正經, 文藝, 黑暗)
• Category filtering and one-click application
• Service: PromptTemplateService

Custom Judge Personas

• Host-configurable judge personalities that mix with defaults
• Per-room storage with add/remove UI in lobby settings
• Integrated into round persona selection logic

Spectator Mode

• Late joiners enter as spectators when game in progress
• View-only access, separate from active player list
• Host-toggleable via room settings

Achievement System

• 8 achievement types with stat tracking (wins, streaks, scores)
• Leaderboard and player stats page (/stats)
• Auto-unlock notifications on game completion

Game History

• Full round-by-round recording with themes, judges, scores
• Player-filterable history page (/history)
• Integrated tracking in game lifecycle

Implementation Notes

All services use singleton registration and integrate with existing GameService flow. History and achievements trigger on game completion.

Performance optimizations:

• Static Random instance (thread-safe singleton)
• Dictionary-based O(1) lookups for player name resolution
• Cheat detection threshold extracted to constant

private static readonly Random _random = new Random();
private const int CHEAT_DETECTION_THRESHOLD = 30;

Achievement cloning uses dedicated method to ensure property consistency:

public Achievement Clone(DateTime unlockedAt) => new Achievement
{
    Id = this.Id,
    Type = this.Type,
    // ... all properties
    UnlockedAt = unlockedAt
};

Original prompt

幫我想一下新功能要加什麼

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