refactor(config): make EditorState/ConfirmDeleteState generic over the artifact type

Review feedback: string widening dropped the compile-time guard at the
write/delete boundary right where the Codex panel (the next task) starts
writing into this state. Threading <TType extends string = CcArtifactType>
through EditorState/EditorModal and ConfirmDeleteState/ConfirmDeleteModal
keeps CcConfig.tsx's write/delete calls checked against CcArtifactType by
default while still letting a Codex-typed caller instantiate its own union
later, removing the two `as CcArtifactType` casts.

client/src/components/config/EditorModal.tsx

@@ -10,18 +10,19 @@
 import { useCallback, useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { Pencil, X, Save, AlertCircle } from "lucide-react";
+import type { CcArtifactType } from "../../lib/api";
 
-export type EditorState =
+export type EditorState<TType extends string = CcArtifactType> =
   | {
       mode: "create";
-      type: string;
+      type: TType;
       defaultScope: "user" | "project";
       template: string;
       project?: string; // set for type === "auto-memory"
     }
   | {
       mode: "edit";
-      type: string;
+      type: TType;
       scope: "user" | "project" | "auto-memory";
       name: string;
       filePath: string;
@@ -29,12 +30,12 @@ export type EditorState =
     }
   | null;
 
-interface EditorModalProps {
-  state: NonNullable<EditorState>;
+interface EditorModalProps<TType extends string = CcArtifactType> {
+  state: NonNullable<EditorState<TType>>;
   fetchContent: (filePath: string) => Promise<string>;
   onClose: () => void;
   onSave: (args: {
-    type: string;
+    type: TType;
     targetScope: "user" | "project" | "auto-memory";
     name: string | undefined;
     content: string;
@@ -42,7 +43,12 @@ interface EditorModalProps {
   }) => Promise<void>;
 }
 
-export function EditorModal({ state, fetchContent, onClose, onSave }: EditorModalProps) {
+export function EditorModal<TType extends string = CcArtifactType>({
+  state,
+  fetchContent,
+  onClose,
+  onSave,
+}: EditorModalProps<TType>) {
   const { t } = useTranslation("ccConfig");
   const isCreate = state.mode === "create";
   const isAutoMemory = state.type === "auto-memory";