Expose explicit LiveSync batching and honour save failures

Show the batching choice for the current synchronisation mode while
preserving both mode preferences. Observe local save failures before
file-open work and report failed asynchronous unload preparation.

Record the accepted recovery and batching contract, update the primary
settings documentation, and add two-device runtime coverage for batching,
deletions, saved settings, and interrupted local processing.

Requires Commonlib commit 72bdc66af5d7338d8f2f69ebe83c3866def93360.
Update the exact registry dependency when its package version is published.

Validation: full repository check; latest packed dependency type checks,
production build, 1,373 unit tests (one skipped), and six focused runtime
recovery cases. The earlier implementation passed the full 23-case runtime
comparison and five additional interruption conditions.

src/modules/features/SettingDialogue/PaneSyncSettings.ts

@@ -171,20 +171,18 @@ export function paneSyncSettings(
         }
     });
 
-    void addPanel(
-        paneEl,
-        $msg("obsidianLiveSyncSettingTab.titleUpdateThinning"),
-        undefined,
-        visibleOnly(() => !this.isConfiguredAs("syncMode", "LIVESYNC"))
-    ).then((paneEl) => {
-        new Setting(paneEl).autoWireToggle("batchSave");
+    void addPanel(paneEl, $msg("obsidianLiveSyncSettingTab.titleUpdateThinning")).then((paneEl) => {
+        const inLiveSyncMode = () => this.isConfiguredAs("syncMode", "LIVESYNC");
+        const batchEnabled = () => this.isConfiguredAs(inLiveSyncMode() ? "batchSaveInLiveSync" : "batchSave", true);
+        new Setting(paneEl).autoWireToggle("batchSave", { onUpdate: visibleOnly(() => !inLiveSyncMode()) });
+        new Setting(paneEl).autoWireToggle("batchSaveInLiveSync", { onUpdate: visibleOnly(inLiveSyncMode) });
         new Setting(paneEl).autoWireNumeric("batchSaveMinimumDelay", {
             acceptZero: true,
-            onUpdate: visibleOnly(() => this.isConfiguredAs("batchSave", true)),
+            onUpdate: visibleOnly(batchEnabled),
         });
         new Setting(paneEl).autoWireNumeric("batchSaveMaximumDelay", {
             acceptZero: true,
-            onUpdate: visibleOnly(() => this.isConfiguredAs("batchSave", true)),
+            onUpdate: visibleOnly(batchEnabled),
         });
     });
 

src/modules/features/SettingDialogue/PaneSyncSettings.unit.spec.ts

@@ -0,0 +1,98 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { DEFAULT_SETTINGS } from "@vrtmrz/livesync-commonlib/compat/common/types";
+import type { ObsidianLiveSyncSettingTab } from "./ObsidianLiveSyncSettingTab";
+import type { OnUpdateFunc, PageFunctions } from "./SettingPane";
+
+const controls = vi.hoisted(() => new Map<string, { onUpdate?: () => { visibility?: boolean } }>());
+vi.mock("@/common/translation", () => ({ $msg: (key: string) => key }));
+vi.mock("@vrtmrz/livesync-commonlib/compat/common/logger", () => ({ Logger: vi.fn() }));
+vi.mock("./LiveSyncSetting.ts", () => ({
+    LiveSyncSetting: class {
+        autoWireDropDown(key: string, options = {}) {
+            controls.set(key, options);
+            return this;
+        }
+        autoWireToggle(key: string, options = {}) {
+            controls.set(key, options);
+            return this;
+        }
+        autoWireNumeric(key: string, options = {}) {
+            controls.set(key, options);
+            return this;
+        }
+    },
+}));
+
+import { paneSyncSettings } from "./PaneSyncSettings";
+
+function setup(liveSync: boolean, batchSave: boolean, batchSaveInLiveSync: boolean) {
+    const callbacks = new Map<string, (value: string) => Promise<void>>();
+    const panels = new Map<string, OnUpdateFunc | undefined>();
+    const tab = {
+        editingSettings: { ...DEFAULT_SETTINGS, liveSync, batchSave, batchSaveInLiveSync },
+        services: { API: { isMobile: () => false }, control: { applySettings: vi.fn(async () => {}) } },
+        addOnSaved: (key: string, callback: (value: string) => Promise<void>) => callbacks.set(key, callback),
+        isConfiguredAs(key: string, value: unknown) {
+            if (key === "syncMode") {
+                return (
+                    (this.editingSettings.liveSync
+                        ? "LIVESYNC"
+                        : this.editingSettings.periodicReplication
+                          ? "PERIODIC"
+                          : "ONEVENTS") === value
+                );
+            }
+            return this.editingSettings[key as keyof typeof this.editingSettings] === value;
+        },
+        saveSettings: vi.fn(async () => {}),
+        requestCatalogueRefresh: vi.fn(),
+    };
+    const functions = {
+        addPanel: (_element: HTMLElement, title: string, _callback: unknown, onUpdate?: OnUpdateFunc) => ({
+            then(callback: (element: HTMLElement) => void) {
+                if (!title.endsWith("titleSynchronizationMethod") && !title.endsWith("titleUpdateThinning")) return;
+                panels.set(title, onUpdate);
+                callback({} as HTMLElement);
+            },
+        }),
+    } as unknown as PageFunctions;
+    paneSyncSettings.call(tab as unknown as ObsidianLiveSyncSettingTab, {} as HTMLElement, functions);
+    return { tab, callbacks, panels };
+}
+
+function visible(key: string): boolean {
+    const control = controls.get(key);
+    if (!control) throw new Error(`Missing setting control: ${key}`);
+    return control.onUpdate?.().visibility !== false;
+}
+
+beforeEach(() => controls.clear());
+
+describe("mode-specific database batching settings", () => {
+    it.each([
+        { liveSync: true, batchSave: true, batchSaveInLiveSync: false, delays: false },
+        { liveSync: true, batchSave: false, batchSaveInLiveSync: true, delays: true },
+        { liveSync: false, batchSave: true, batchSaveInLiveSync: false, delays: true },
+        { liveSync: false, batchSave: false, batchSaveInLiveSync: true, delays: false },
+    ])("shows the current mode choice and its shared delays: %j", ({ delays, ...settings }) => {
+        const { panels } = setup(settings.liveSync, settings.batchSave, settings.batchSaveInLiveSync);
+        expect(panels.get("obsidianLiveSyncSettingTab.titleUpdateThinning")?.().visibility).not.toBe(false);
+        expect(visible("batchSave")).toBe(!settings.liveSync);
+        expect(visible("batchSaveInLiveSync")).toBe(settings.liveSync);
+        expect(visible("batchSaveMinimumDelay")).toBe(delays);
+        expect(visible("batchSaveMaximumDelay")).toBe(delays);
+    });
+
+    it.each([
+        [true, false],
+        [false, true],
+    ])("retains both batching choices across mode changes: %j", async (batchSave, batchSaveInLiveSync) => {
+        const { tab, callbacks } = setup(false, batchSave, batchSaveInLiveSync);
+        const switchMode = callbacks.get("syncMode")!;
+        for (const mode of ["LIVESYNC", "PERIODIC", "ONEVENTS", "LIVESYNC"]) {
+            await switchMode(mode);
+            expect(tab.editingSettings).toMatchObject({ batchSave, batchSaveInLiveSync });
+        }
+        expect(tab.services.control.applySettings).toHaveBeenCalledTimes(4);
+    });
+});