feat(claude-desktop): add 3P provider switching with proxy gateway

Adds a new ClaudeDesktop AppType that writes Claude Desktop's third-party
inference profile under configLibrary/, sharing _meta.json with other
launchers (Ollama-compatible) so cc-switch can coexist with them.

Two switch modes:
- direct: provider already exposes claude-* / anthropic/claude-* model
  ids on Anthropic Messages, Claude Desktop connects to it directly.
- proxy: cc-switch's local proxy acts as the inference gateway,
  presenting only claude-* route names to Claude Desktop and mapping
  them to real upstream models. Required after Anthropic restricted
  Claude Desktop to claude-family ids.

Backend:
- New module claude_desktop_config with snapshot/rollback, official seed
  bypass, /claude-desktop/v1/{models,messages} routes, and a single
  source of truth for default proxy routes.
- Gateway token persisted in SQLite, validated on every proxied request.
- get_claude_desktop_status surfaces drift signals (stale models,
  missing routes, proxy stopped, base URL mismatch, missing token).

Frontend:
- Slim ClaudeDesktopProviderForm independent from ProviderForm,
  controlled by a top-level appId guard.
- ProviderList banner consumes the status query (5s polling) and
  renders actionable diagnostics.
- ClaudeDesktopRouteToggle in the header to start/stop the local
  gateway without touching takeover state.
- Three-locale i18n synchronised.

src-tauri/src/services/proxy.rs

@@ -466,7 +466,7 @@ impl ProxyService {
             AppType::Claude => self.read_claude_live()?,
             AppType::Codex => self.read_codex_live()?,
             AppType::Gemini => self.read_gemini_live()?,
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features
                 return Err("该应用不支持代理功能".to_string());
             }
@@ -683,7 +683,7 @@ impl ProxyService {
                     }
                 }
             }
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features, skip silently
             }
         }
@@ -864,7 +864,7 @@ impl ProxyService {
             AppType::Claude => ("claude", self.read_claude_live()?),
             AppType::Codex => ("codex", self.read_codex_live()?),
             AppType::Gemini => ("gemini", self.read_gemini_live()?),
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features
                 return Err("该应用不支持代理功能".to_string());
             }
@@ -1008,7 +1008,7 @@ impl ProxyService {
                 self.write_gemini_live(&live_config)?;
                 log::info!("Gemini Live 配置已接管，代理地址: {proxy_url}");
             }
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features
                 return Err("该应用不支持代理功能".to_string());
             }
@@ -1061,7 +1061,7 @@ impl ProxyService {
                     let _ = self.write_gemini_live(&live_config);
                 }
             }
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features, skip silently
             }
         }
@@ -1101,7 +1101,7 @@ impl ProxyService {
                     log::info!("Gemini Live 配置已恢复");
                 }
             }
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features, skip silently
             }
         }
@@ -1192,7 +1192,7 @@ impl ProxyService {
             AppType::Claude => self.write_claude_live(config),
             AppType::Codex => self.write_codex_live(config),
             AppType::Gemini => self.write_gemini_live(config),
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features
                 Err("该应用不支持代理功能".to_string())
             }
@@ -1213,7 +1213,7 @@ impl ProxyService {
                 Ok(config) => Self::is_gemini_live_taken_over(&config),
                 Err(_) => false,
             },
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy takeover
                 false
             }
@@ -1256,7 +1256,7 @@ impl ProxyService {
             AppType::Claude => self.cleanup_claude_takeover_placeholders_in_live(),
             AppType::Codex => self.cleanup_codex_takeover_placeholders_in_live(),
             AppType::Gemini => self.cleanup_gemini_takeover_placeholders_in_live(),
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 // These apps don't support proxy features
                 Ok(())
             }
@@ -1520,7 +1520,7 @@ impl ProxyService {
                 serde_json::to_string(&env_backup)
                     .map_err(|e| format!("序列化 Gemini 配置失败: {e}"))?
             }
-            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes => {
+            AppType::OpenCode | AppType::OpenClaw | AppType::Hermes | AppType::ClaudeDesktop => {
                 return Err(format!("未知的应用类型: {app_type}"));
             }
         };