Rename AuthMode to Backend, fix LiteLLM variant typo, add image update alerts, clean up Settings

- Fix serde deserialization error: TypeScript sent "lit_llm" but Rust expected "lite_llm"
- Rename AuthMode enum to Backend across Rust and TypeScript (with serde alias for backward compat)
- Add container image update checking via registry digest comparison
- Improve Settings page: fix image address display spacing, remove per-project auth section
- Update UI labels from "Auth" to "Backend" throughout

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/lib/tauri-commands.ts

@@ -1,5 +1,5 @@
 import { invoke } from "@tauri-apps/api/core";
-import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, McpServer, FileEntry } from "./types";
+import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, ImageUpdateInfo, McpServer, FileEntry } from "./types";
 
 // Docker
 export const checkDocker = () => invoke<boolean>("check_docker");
@@ -83,3 +83,5 @@ export const uploadFileToContainer = (projectId: string, hostPath: string, conta
 export const getAppVersion = () => invoke<string>("get_app_version");
 export const checkForUpdates = () =>
   invoke<UpdateInfo | null>("check_for_updates");
+export const checkImageUpdate = () =>
+  invoke<ImageUpdateInfo | null>("check_image_update");

app/src/lib/types.ts

@@ -20,7 +20,7 @@ export interface Project {
   paths: ProjectPath[];
   container_id: string | null;
   status: ProjectStatus;
-  auth_mode: AuthMode;
+  backend: Backend;
   bedrock_config: BedrockConfig | null;
   ollama_config: OllamaConfig | null;
   litellm_config: LiteLlmConfig | null;
@@ -45,7 +45,7 @@ export type ProjectStatus =
   | "stopping"
   | "error";
 
-export type AuthMode = "anthropic" | "bedrock" | "ollama" | "lit_llm";
+export type Backend = "anthropic" | "bedrock" | "ollama" | "lite_llm";
 
 export type BedrockAuthMethod = "static_credentials" | "profile" | "bearer_token";
 
@@ -116,6 +116,7 @@ export interface AppSettings {
   dismissed_update_version: string | null;
   timezone: string | null;
   default_microphone: string | null;
+  dismissed_image_digest: string | null;
 }
 
 export interface UpdateInfo {
@@ -133,6 +134,12 @@ export interface ReleaseAsset {
   size: number;
 }
 
+export interface ImageUpdateInfo {
+  remote_digest: string;
+  local_digest: string | null;
+  remote_updated_at: string | null;
+}
+
 export type McpTransportType = "stdio" | "http";
 
 export interface McpServer {