refactor(claude-desktop): drop displayName from model route schema

Claude Desktop's new model menu reads model IDs directly and ignores the
display_name field, so a separate displayName slot added UI noise without
any product value. Collapse the routeId / model / displayName tuple down
to routeId / model, and let the route ID carry the user-visible name
through a non-editable claude- prefix rendered next to the input.

Drop display_name from ClaudeDesktopModelRoute, ClaudeDesktopDefaultRoute,
and ResolvedModelRoute on the Rust side plus the matching TS interfaces,
stop emitting it in /v1/models responses, derive route IDs from upstream
model IDs when picked via the model dropdown, and update zh/en/ja copy to
describe the new two-field layout.

src-tauri/src/commands/provider.rs

@@ -255,7 +255,6 @@ fn suggested_claude_desktop_routes(
         env: &serde_json::Map<String, serde_json::Value>,
         route_id: &str,
         env_key: &str,
-        display_name: &str,
     ) {
         if let Some(model) = env
             .get(env_key)
@@ -267,7 +266,6 @@ fn suggested_claude_desktop_routes(
                 route_id.to_string(),
                 crate::provider::ClaudeDesktopModelRoute {
                     model: model.to_string(),
-                    display_name: Some(display_name.to_string()),
                     supports_1m: Some(true),
                 },
             );
@@ -275,24 +273,12 @@ fn suggested_claude_desktop_routes(
     }
 
     for spec in crate::claude_desktop_config::DEFAULT_PROXY_ROUTES {
-        add_route(
-            &mut routes,
-            env,
-            spec.route_id,
-            spec.env_key,
-            spec.display_name,
-        );
+        add_route(&mut routes, env, spec.route_id, spec.env_key);
     }
 
     let primary_route = crate::claude_desktop_config::DEFAULT_PROXY_ROUTES[0];
     if !routes.contains_key(primary_route.route_id) {
-        add_route(
-            &mut routes,
-            env,
-            primary_route.route_id,
-            "ANTHROPIC_MODEL",
-            primary_route.display_name,
-        );
+        add_route(&mut routes, env, primary_route.route_id, "ANTHROPIC_MODEL");
     }
 
     (!routes.is_empty()).then_some(routes)