feat: add project profiles for snapshot-based config switching

Add a profile feature that captures the current provider, MCP,
skills and prompt state for Claude Code and Codex as a named
snapshot, and re-applies it in one click from the header switcher
or the tray Projects submenu.

- New profiles table (schema v12) with current marker in settings
- ProfileService orchestrates the four existing switch primitives
  (provider first, then MCP diff, skills diff, prompt enable)
- Best-effort apply: dangling references become warnings, no rollback
- Header combobox switcher + snapshot-style manage dialog
- Tray Projects submenu shared with the UI apply/event pipeline
- i18n for zh/en/ja/zh-TW under the new profiles domain
- Integration tests covering roundtrip, dangling refs and clear

src-tauri/src/database/mod.rs

@@ -38,6 +38,7 @@ pub(crate) use dao::proxy::{
     PRICING_SOURCE_RESPONSE,
 };
 pub use dao::FailoverQueueItem;
+pub use dao::Profile;
 
 use crate::config::get_app_config_dir;
 use crate::error::AppError;
@@ -49,7 +50,7 @@ use std::sync::Mutex;
 
 /// 当前 Schema 版本号
 /// 每次修改表结构时递增，并在 schema.rs 中添加相应的迁移逻辑
-pub(crate) const SCHEMA_VERSION: i32 = 11;
+pub(crate) const SCHEMA_VERSION: i32 = 12;
 
 /// 安全地序列化 JSON，避免 unwrap panic
 pub(crate) fn to_json_string<T: Serialize>(value: &T) -> Result<String, AppError> {