fix(editor): surface failed timeline saves

src/components/ai-edition/NewEditorShell.tsx

@@ -302,15 +302,9 @@ export function NewEditorShell() {
 		// 3. Handle request-save-before-close from Electron
 		const unsubSaveBeforeClose = window.electronAPI.onRequestSaveBeforeClose(async () => {
 			const doc = useProjectStore.getState().document;
-			if (doc) {
-				try {
-					await saveDocument(doc);
-					return true;
-				} catch {
-					toast.error("Failed to save before closing");
-					return false;
-				}
-			}
+			// The store already toasted the reason; answering false is what keeps the
+			// window open on top of it.
+			if (doc) return await saveDocument(doc);
 			return true;
 		});
 
@@ -618,14 +612,7 @@ export function NewEditorShell() {
 	const handleSave = useCallback(async () => {
 		const doc = useProjectStore.getState().document;
 		if (!doc) return;
-		try {
-			await saveDocument(doc);
-			toast.success("Project saved");
-		} catch (err) {
-			toast.error("Save failed", {
-				description: err instanceof Error ? err.message : String(err),
-			});
-		}
+		if (await saveDocument(doc)) toast.success("Project saved");
 	}, [saveDocument]);
 
 	// Native File menu (electron/main.ts) → v4 actions. The menu is shown via
@@ -653,13 +640,7 @@ export function NewEditorShell() {
 			const doc = useProjectStore.getState().document;
 			if (!doc) return;
 			if (title === doc.project.title) return;
-			try {
-				await saveDocument({ ...doc, project: { ...doc.project, title } });
-			} catch (err) {
-				toast.error("Rename failed", {
-					description: err instanceof Error ? err.message : String(err),
-				});
-			}
+			await saveDocument({ ...doc, project: { ...doc.project, title } });
 		},
 		[saveDocument],
 	);
@@ -680,13 +661,12 @@ export function NewEditorShell() {
 				}
 				if (choice === "save") {
 					const doc = useProjectStore.getState().document;
-					if (doc) {
-						try {
-							await saveDocument(doc);
-						} catch {
-							resolve("cancel");
-							return;
-						}
+					// A failed save cancels the action that prompted this dialog. The store has
+					// already said why -- which is what the bare `catch {}` here used to swallow,
+					// leaving the window refusing to close with nothing on screen explaining it.
+					if (doc && !(await saveDocument(doc))) {
+						resolve("cancel");
+						return;
 					}
 				}
 				if (action === "record") {
@@ -845,13 +825,8 @@ export function NewEditorShell() {
 					if (choice === "cancel") return;
 					if (choice === "save") {
 						const doc = useProjectStore.getState().document;
-						if (doc) {
-							try {
-								await saveDocument(doc);
-							} catch {
-								return;
-							}
-						}
+						// Stay put if the save did not land -- the store has already said why.
+						if (doc && !(await saveDocument(doc))) return;
 					}
 					setNewProjectOpen(true);
 				})();
@@ -864,13 +839,8 @@ export function NewEditorShell() {
 					if (choice === "cancel") return;
 					if (choice === "save") {
 						const doc = useProjectStore.getState().document;
-						if (doc) {
-							try {
-								await saveDocument(doc);
-							} catch {
-								return;
-							}
-						}
+						// Stay put if the save did not land -- the store has already said why.
+						if (doc && !(await saveDocument(doc))) return;
 					}
 					setOpenProjectOpen(true);
 				})();

src/components/ai-edition/v4/V4Timeline.tsx

@@ -1059,6 +1059,10 @@ export function V4Timeline({
 				return;
 			}
 			const added = await tl.addZoomsBulk(suggestions);
+			// A failed write returns 0 and has already toasted why. Without this the user
+			// got "Added 0 automatic zooms" stacked on top of "Failed to save project",
+			// with no zoom anywhere -- a success message for something that did not happen.
+			if (added === 0) return;
 			toast.success(
 				t(added === 1 ? "toolbar.addedAutoZoom" : "toolbar.addedAutoZoomPlural", { count: added }),
 			);

src/i18n/toastText.ts

@@ -0,0 +1,25 @@
+// Translation for toasts fired OUTSIDE React -- stores, and anything else that reports
+// to the user without a component around it to call `useScopedT`.
+
+import { DEFAULT_LOCALE, type I18nNamespace, LOCALE_STORAGE_KEY, type Locale } from "./config";
+import { getAvailableLocales, translate } from "./loader";
+
+/**
+ * Toasts fired outside React still have to speak the user's language. Same source as
+ * `I18nProvider` (stored preference, else the default), validated so a stale value
+ * cannot push `translate` onto a locale it does not have.
+ */
+export function toastText(
+	namespace: I18nNamespace,
+	key: string,
+	vars?: Record<string, string | number>,
+): string {
+	let locale: Locale = DEFAULT_LOCALE;
+	try {
+		const stored = localStorage.getItem(LOCALE_STORAGE_KEY);
+		if (stored && getAvailableLocales().includes(stored as Locale)) locale = stored as Locale;
+	} catch {
+		// localStorage may be unavailable -- the default locale is a fine answer.
+	}
+	return translate(locale, namespace, key, vars);
+}

src/lib/ai-edition/store/projectStore.test.ts

@@ -297,6 +297,58 @@ describe("useProjectStore", () => {
 		expect(toastMocks.error.mock.calls[0][0]).toContain("video.mp4");
 	});
 
+	// The save boundary. Every write in the app funnels through `saveDocument`, and
+	// almost every caller `void`s it from a click handler, so what this function does
+	// with a failure IS what the user sees.
+	describe("saveDocument reports a failed write instead of rejecting", () => {
+		it("resolves false, tells the user, and leaves the document alone", async () => {
+			useProjectStore.setState({
+				projectId: "proj_test",
+				document: sampleDoc,
+				revision: 3,
+				status: "ready",
+				dirty: true,
+			});
+			bridgeMocks.save.mockResolvedValue({ success: false, error: "EACCES" });
+
+			const edited = { ...sampleDoc, project: { ...sampleDoc.project, title: "Edited" } };
+			await expect(useProjectStore.getState().saveDocument(edited)).resolves.toBe(false);
+
+			expect(toastMocks.error).toHaveBeenCalledWith("Failed to save project", {
+				description: "EACCES",
+			});
+			const state = useProjectStore.getState();
+			expect(state.document?.project.title).toBe("Test");
+			expect(state.revision).toBe(3);
+			// Still dirty: `dirty` is the only input to the beforeunload guard and to
+			// `setHasUnsavedChanges`, so a failed write is the last moment to claim clean.
+			expect(state.dirty).toBe(true);
+		});
+
+		it("never rejects, so a detached caller cannot leak an unhandled rejection", async () => {
+			useProjectStore.setState({ projectId: "proj_test", document: sampleDoc, dirty: true });
+			bridgeMocks.save.mockRejectedValue(new Error("bridge is gone"));
+
+			await expect(useProjectStore.getState().saveDocument(sampleDoc)).resolves.toBe(false);
+			expect(toastMocks.error).toHaveBeenCalledWith("Failed to save project", {
+				description: "bridge is gone",
+			});
+		});
+
+		it("resolves true and commits on success", async () => {
+			const saved = { ...sampleDoc, project: { ...sampleDoc.project, title: "Saved" } };
+			useProjectStore.setState({ projectId: "proj_test", document: sampleDoc, dirty: true });
+			bridgeMocks.save.mockResolvedValue({ success: true, document: saved });
+
+			await expect(useProjectStore.getState().saveDocument(saved)).resolves.toBe(true);
+
+			expect(toastMocks.error).not.toHaveBeenCalled();
+			const state = useProjectStore.getState();
+			expect(state.document?.project.title).toBe("Saved");
+			expect(state.dirty).toBe(false);
+		});
+	});
+
 	it("removeAsset requires a loaded project", async () => {
 		await expect(useProjectStore.getState().removeAsset("asset_x")).rejects.toThrow(
 			"No project loaded",

src/lib/ai-edition/store/projectStore.ts

@@ -1,4 +1,6 @@
+import { toast } from "sonner";
 import { create } from "zustand";
+import { toastText } from "@/i18n/toastText";
 import { nativeBridgeClient } from "@/native/client";
 import {
 	type Interval,
@@ -36,7 +38,17 @@ export interface ProjectState {
 	refresh: () => Promise<void>;
 	addAsset: (path: string, label?: string) => Promise<AxcutAsset | null>;
 	removeAsset: (assetId: string) => Promise<void>;
-	saveDocument: (document: AxcutDocument) => Promise<void>;
+	/**
+	 * Write the document to disk. Resolves `true` when it landed, `false` when it did
+	 * not -- and a `false` has ALREADY been reported to the user and logged, so a
+	 * caller that ignores it is choosing not to react, not choosing to stay silent.
+	 *
+	 * It never rejects, by design. Every save in the app funnels through here and
+	 * almost all of them are `void`-ed from a click handler, so a rejection here was
+	 * an unhandled rejection in the renderer with no toast, no log and no clue --
+	 * change a caption font on a read-only project and the edit was simply gone.
+	 */
+	saveDocument: (document: AxcutDocument) => Promise<boolean>;
 	setDocument: (document: AxcutDocument) => void;
 	replaceTimeline: (intervals: Interval[], reason: string) => Promise<void>;
 	restoreFullTimeline: () => Promise<void>;
@@ -169,8 +181,10 @@ export const useProjectStore = create<ProjectState>((set, get) => ({
 							a.id === addedAsset.id ? { ...a, cameraTrack: linked } : a,
 						),
 					};
-					await get().saveDocument(next);
-					document = parseDocument(next);
+					// Only adopt the linked document if it actually reached disk -- otherwise
+					// the caller is handed a document claiming a camera link the file does not
+					// have. The store has already told the user the write failed.
+					if (await get().saveDocument(next)) document = parseDocument(next);
 				}
 				// success:false just means no camera was found for this asset —
 				// the normal case for a plain imported video. Nothing to surface.
@@ -212,17 +226,32 @@ export const useProjectStore = create<ProjectState>((set, get) => ({
 	},
 
 	async saveDocument(document) {
-		const result = await nativeBridgeClient.aiEdition.save(document);
-		if (!result.success || !result.document) {
-			throw new Error(result.error ?? "Failed to save project");
+		try {
+			const result = await nativeBridgeClient.aiEdition.save(document);
+			if (!result.success || !result.document) {
+				throw new Error(result.error ?? "Failed to save project");
+			}
+			const parsed = parseDocument(result.document);
+			set({
+				document: parsed,
+				revision: get().revision + 1,
+				dirty: false,
+				lastSavedAt: new Date(),
+			});
+			return true;
+		} catch (error) {
+			// Logged as well as toasted: a toast is gone in five seconds, and "my edit
+			// disappeared" gets reported much later than that.
+			console.error("[project] failed to save document:", error);
+			toast.error(toastText("editor", "project.failedToSave"), {
+				description: error instanceof Error ? error.message : String(error),
+			});
+			// `dirty` is deliberately left alone. It is the only input to the
+			// `beforeunload` guard and to `setHasUnsavedChanges`, so clearing it here
+			// would let the window close without a prompt on the one path where there is
+			// definitely something unsaved.
+			return false;
 		}
-		const parsed = parseDocument(result.document);
-		set({
-			document: parsed,
-			revision: get().revision + 1,
-			dirty: false,
-			lastSavedAt: new Date(),
-		});
 	},
 
 	setDocument(document) {

src/lib/ai-edition/store/transcriptionStore.ts

@@ -25,8 +25,7 @@
 import { useEffect, useMemo } from "react";
 import { toast } from "sonner";
 import { create } from "zustand";
-import { DEFAULT_LOCALE, LOCALE_STORAGE_KEY, type Locale } from "@/i18n/config";
-import { getAvailableLocales, translate } from "@/i18n/loader";
+import { toastText as translateToast } from "@/i18n/toastText";
 import { transcribeAsset, withTranscript } from "../document/transcribe";
 import type { AxcutDocument } from "../schema";
 import {
@@ -85,21 +84,9 @@ function hasLocalSttEngine(): boolean {
 	return typeof window.electronAPI?.stt?.transcribe === "function";
 }
 
-/**
- * Toasts fired outside React still have to speak the user's language. Same
- * source as `I18nProvider` (stored preference, else the default), validated so
- * a stale value can't push `translate` onto a locale it doesn't have.
- */
-function toastText(key: string, vars?: Record<string, string | number>): string {
-	let locale: Locale = DEFAULT_LOCALE;
-	try {
-		const stored = localStorage.getItem(LOCALE_STORAGE_KEY);
-		if (stored && getAvailableLocales().includes(stored as Locale)) locale = stored as Locale;
-	} catch {
-		// localStorage may be unavailable — the default locale is a fine answer.
-	}
-	return translate(locale, "editor", key, vars);
-}
+/** This store's toasts all live in the `editor` namespace. */
+const toastText = (key: string, vars?: Record<string, string | number>) =>
+	translateToast("editor", key, vars);
 
 export const useTranscriptionStore = create<TranscriptionState>((set, get) => ({
 	projectId: null,
@@ -321,24 +308,26 @@ async function persistPermanentFailure(
 	const doc = project.document;
 	if (!doc || doc.project.id !== projectId) return;
 	if (!doc.assets.some((a) => a.id === assetId)) return;
-	try {
-		await project.saveDocument({
-			...doc,
-			assets: doc.assets.map((a) =>
-				a.id === assetId
-					? {
-							...a,
-							transcriptionFailure: {
-								kind,
-								message: failure.message,
-								at: new Date().toISOString(),
-							},
-						}
-					: a,
-			),
-		});
-	} catch (error) {
-		console.warn("[transcription] could not persist the failure on the asset:", error);
+	// Best-effort bookkeeping: `saveDocument` reports its own failures and resolves
+	// false rather than throwing, and a note on the asset is not worth a second
+	// message on top of the one the user already got.
+	const persisted = await project.saveDocument({
+		...doc,
+		assets: doc.assets.map((a) =>
+			a.id === assetId
+				? {
+						...a,
+						transcriptionFailure: {
+							kind,
+							message: failure.message,
+							at: new Date().toISOString(),
+						},
+					}
+				: a,
+		),
+	});
+	if (!persisted) {
+		console.warn("[transcription] could not persist the failure on the asset");
 	}
 }