feat: port TechLog Studio editors

src/features/tech-log/presentation/studio/studio-provider.tsx

@@ -6,7 +6,16 @@ import {
 } from "react";
 
 import type { StudioGateway } from "../../application/ports/studio-gateway.ts";
-import { StudioContext, type StudioContextValue } from "./use-studio.ts";
+import type {
+  WorkingCopy,
+  WorkingCopyInput,
+} from "../../contracts/studio/contract.ts";
+import {
+  StudioContext,
+  type StudioContextValue,
+  type StudioEditorState,
+  type StudioEditorStatus,
+} from "./use-studio.ts";
 
 type StudioProviderProps = Readonly<{
   children: ReactNode;
@@ -25,16 +34,41 @@ export function StudioProvider({
   navigate = defaultNavigate,
 }: StudioProviderProps) {
   const [gateway] = useState<StudioGateway>(() => createGateway());
+  const [editor, setEditor] = useState<StudioEditorState | null>(null);
   const [requestAnnouncement, setRequestAnnouncement] = useState("");
   const navigateInternal = useCallback((href: string) => navigate(href), [navigate]);
+  const beginEditor = useCallback((saved: WorkingCopy, draft: WorkingCopyInput) => {
+    setEditor({ documentId: saved.id, saved, draft, status: "CLEAN" });
+  }, []);
+  const updateEditorDraft = useCallback((draft: WorkingCopyInput) => {
+    setEditor((current) => current ? { ...current, draft, status: "DIRTY" } : current);
+  }, []);
+  const setEditorStatus = useCallback((status: StudioEditorStatus) => {
+    setEditor((current) => current ? { ...current, status } : current);
+  }, []);
+  const clearEditor = useCallback(() => setEditor(null), []);
   const value = useMemo<StudioContextValue>(
     () => ({
       gateway,
+      editor,
       requestAnnouncement,
       setRequestAnnouncement,
       navigateInternal,
+      beginEditor,
+      updateEditorDraft,
+      setEditorStatus,
+      clearEditor,
     }),
-    [gateway, navigateInternal, requestAnnouncement],
+    [
+      beginEditor,
+      clearEditor,
+      editor,
+      gateway,
+      navigateInternal,
+      requestAnnouncement,
+      setEditorStatus,
+      updateEditorDraft,
+    ],
   );
 
   return (