[WIP] Add complete context system for Bot commands and handlers

[Copilot]

• Add context config/attribute/DTO and lazy store types
• Add context DB entities and repository/service interfaces
• Implement context repositories and context service with Redis fallback
• Update command definition and command handler for context injection/filter routing
• Build and run tests for verification

Original prompt

概述

为 Bot 的命令和 CallbackQuery handler 添加一套完整的 会话上下文（Context）系统，支持：

• 私聊上下文（PrivateContext）与群聊上下文（GroupContext）类型区分
• handler 方法通过参数类型声明所需 context，框架自动注入
• ContextFilterAttribute 标记 handler 所需的 Mode，实现多步骤交互路由
• 懒加载：仅在 handler 实际访问 context 时才触发 IO
• Redis TTL 热缓存 + DB 持久化双写，Redis 故障时自动回退到 DB
• 启动时预扫描参数类型，无 context 参数的命令零 IO

---

需要新建的文件

1. 配置类

XinjingDaily.Bot.Infrastructure/Configs/ContextConfig.cs

namespace XinjingDaily.Bot.Infrastructure.Configs;

/// <summary>
/// Context 系统配置
/// </summary>
public sealed record ContextConfig
{
    /// <summary>
    /// Redis TTL（秒），默认 1800（30 分钟）。
    /// </summary>
    public int TtlSeconds { get; init; } = 1800;
}

在 AppSettings 中新增字段：

public ContextConfig? Context { get; init; }

---

2. Redis DTO

XinjingDaily.Bot.Infrastructure/Bot/Context/ContextRedisDto.cs

namespace XinjingDaily.Bot.Infrastructure.Bot.Context;

public sealed class ContextRedisDto
{
    public int DbId { get; set; }
    public int UserId { get; set; }
    public long ChatId { get; set; }
    public string Command { get; set; } = string.Empty;
    public string Mode { get; set; } = string.Empty;
    public Dictionary<string, string> Data { get; set; } = [];
    public DateTime ModifyAt { get; set; } = DateTime.UtcNow;
}

---

3. Attribute

XinjingDaily.Bot.Infrastructure/Attribute/ContextFilterAttribute.cs

namespace XinjingDaily.Bot.Infrastructure.Attribute;

[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public sealed class ContextFilterAttribute : System.Attribute
{
    public string Mode { get; }
    public ContextFilterAttribute(string mode) => Mode = mode;
}

---

4. 懒加载 Store

XinjingDaily.Bot.Infrastructure/Bot/Context/LazyContextStore.cs

实现要点：

• 构造时只保存 Func<Task<ContextRedisDto>> 加载函数，不执行 IO
• IsLoaded、IsDirty 属性
• EnsureLoadedAsync()：首次调用触发 IO，后续直接返回
• GetModeAsync()、SetModeAsync(string)、ClearModeAsync()
• GetAsync<T>(string)、SetAsync<T>(string, T)（超过 2000 字符时抛出 InvalidOperationException）、TryGetAsync<T>(string, Action<T?>)、RemoveAsync(string)、ClearAsync()
• ExportDto()：未加载或无脏数据时返回 null
• MarkClean()、SerializeData()、GetMode()（同步，仅在已加载时有效）、GetDbId()

---

5. PrivateContext

XinjingDaily.Bot.Infrastructure/Bot/Context/PrivateContext.cs

namespace XinjingDaily.Bot.Infrastructure.Bot.Context;

public sealed class PrivateContext
{
    internal LazyContextStore Store { get; }
    internal PrivateContext(LazyContextStore store) { Store = store; }

    // Mode 同步属性（仅已加载时有值）
    public string Mode => Store.IsLoaded ? Store.GetMode() : string.Empty;

    public ValueTask<string> GetModeAsync() => Store.GetModeAsync();
    public ValueTask SetModeAsync(string mode) => Store.SetModeAsync(mode);
    public ValueTask ClearModeAsync() => Store.ClearModeAsync();

    public ValueTask<T?> GetAsync<T>(string key) => Store.GetAsync<T>(key);
    public ValueTask SetAsync<T>(string key, T value) where T : notnull => Store.SetAsync(key, value);
    public ValueTask RemoveAsync(string key) => Store.RemoveAsync(key);
    public ValueTask ClearAsync() => Store.ClearAsync();

    internal bool IsDirty => Store.IsDirty;
}

---

6. GroupContext

XinjingDaily.Bot.Infrastructure/Bot/Context/GroupContext.cs

namespace XinjingDaily.Bot.Infrastructure.Bot.Context;

public sealed class GroupContext
{
    internal LazyContextStore UserStore { get; }
    internal LazyContextStore ChatStore { get; }

    internal GroupContext(LazyContextStore userStore, LazyContextStore chatStore)
    {
        UserStore = userStore;
        ChatStore = chatStore;
    }

    // 用户在群内（默认操作）
    public string Mode => UserStore.IsLoaded ? UserStore.GetMode() : string.Empty;
    public ValueTask<string> GetModeAsync() => UserStore.GetModeAsync();
    public ValueTask SetModeAsync(string mode) => UserStore.SetModeAsync(mode);
    public ValueTask ClearModeAsync() => UserStore.ClearModeAsync();
    public ValueTask<T?> GetAsync<T>(string key) => UserStore.GetAsync<T>(key);
    public ValueTask SetAsync<T>(string key, T value) where T : notnull => UserStore.SetAsync(key, value);
    public ValueTask RemoveAsync(string key) => UserStore.RemoveAsync(key);
    public ValueTask ClearAsync() => UserStore.ClearAsync();

    // 群组公共（Chat 前缀）
    public string ChatMode => ChatStore.IsLoaded ? ChatStore.GetMode() : string.Empty;
    public ValueTask<string> GetChatModeAsync() => ChatStore.GetModeAsync();
    public ValueTask SetChatModeAsync(string mode) => ChatStore.SetModeAsync(mode);
    public ValueTask ClearChatModeAsync() => ChatStore.ClearModeAsync();
    public ValueTask<T?> ChatGetAsync<T>(string key) => ChatStore.GetAsync<T>(key);
    public ValueTask ChatSetAsync<T>(string key, T value) where T : notnull => ChatStore.SetAsync(key, value);
    public ValueTask ChatRemoveAsync(string key) => ChatStore.Rem...

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