fix(effects): add skipDuringSync to task-ui effects and document all usages

Add skipDuringSync() to two selector-based effects in task-ui.effects.ts:
- timeEstimateExceeded$: Prevent spurious notifications during sync
- timeEstimateExceededDismissBanner$: Prevent unexpected banner dismissal

Add explanatory comments to all skipDuringSync() usages explaining why
each is needed:
- focus-mode.effects.ts: 3 effects (autoShowOverlay$, syncTrackingStartToSession$,
  syncTrackingStopToSession$)
- work-context.effects.ts: 1 effect (switchToTodayContextOnSpecialRoutes$)
- task-ui.effects.ts: 2 effects (new additions)

These are defensive measures to prevent selector-based effects from
triggering side effects during sync/hydration when store state changes
rapidly from remote operations.

src/app/features/focus-mode/store/focus-mode.effects.ts

@@ -61,6 +61,8 @@ export class FocusModeEffects {
       this.store.select(selectFocusModeConfig),
       this.store.select(selectIsFocusModeEnabled),
     ]).pipe(
+      // Prevent auto-showing overlay during sync - config/task state changes from
+      // remote ops would otherwise trigger the overlay unexpectedly
       skipDuringSync(),
       switchMap(([cfg, isFocusModeEnabled]) =>
         isFocusModeEnabled && cfg?.isSyncSessionWithTracking && !cfg?.isStartInBackground
@@ -81,6 +83,8 @@ export class FocusModeEffects {
       this.store.select(selectFocusModeConfig),
       this.store.select(selectIsFocusModeEnabled),
     ]).pipe(
+      // Prevent auto-starting/unpausing focus session during sync - currentTaskId
+      // changes from remote ops would otherwise start sessions unexpectedly
       skipDuringSync(),
       switchMap(([cfg, isFocusModeEnabled]) =>
         isFocusModeEnabled && cfg?.isSyncSessionWithTracking
@@ -116,6 +120,9 @@ export class FocusModeEffects {
   // Only triggers when focus mode feature is enabled
   syncTrackingStopToSession$ = createEffect(() =>
     this.taskService.currentTaskId$.pipe(
+      // CRITICAL: Prevent cascading dispatches during sync that cause app freeze.
+      // Without this, rapid currentTaskId changes from remote ops trigger pairwise()
+      // which dispatches pauseFocusSession repeatedly, overwhelming the store.
       skipDuringSync(),
       pairwise(),
       withLatestFrom(

src/app/features/tasks/store/task-ui.effects.ts

@@ -30,6 +30,7 @@ import { GlobalConfigService } from '../../config/global-config.service';
 import { playDoneSound } from '../util/play-done-sound';
 import { Task } from '../task.model';
 import { EMPTY } from 'rxjs';
+import { skipDuringSync } from '../../../util/skip-during-sync.operator';
 import { selectProjectById } from '../../project/store/project.selectors';
 import { Router } from '@angular/router';
 import { NavigateToTaskService } from '../../../core-ui/navigate-to-task/navigate-to-task.service';
@@ -121,6 +122,9 @@ export class TaskUiEffects {
   timeEstimateExceeded$ = createEffect(
     () =>
       this._store$.pipe(select(selectConfigFeatureState)).pipe(
+        // Prevent spurious notifications during sync - currentTask state changes
+        // from remote ops would otherwise trigger "time estimate exceeded" alerts
+        skipDuringSync(),
         switchMap((globalCfg) =>
           globalCfg && globalCfg.timeTracking.isNotifyWhenTimeEstimateExceeded
             ? // reset whenever the current taskId changes (but no the task data, which is polled afterwards)
@@ -152,6 +156,9 @@ export class TaskUiEffects {
   timeEstimateExceededDismissBanner$ = createEffect(
     () =>
       this._store$.pipe(select(selectConfigFeatureState)).pipe(
+        // Prevent unexpected banner dismissal during sync - currentTaskId changes
+        // from remote ops would otherwise dismiss the time estimate exceeded banner
+        skipDuringSync(),
         switchMap((globalCfg) =>
           globalCfg && globalCfg.timeTracking.isNotifyWhenTimeEstimateExceeded
             ? this._bannerService.activeBanner$.pipe(

src/app/features/work-context/store/work-context.effects.ts

@@ -47,6 +47,8 @@ export class WorkContextEffects {
       filter((event): event is NavigationEnd => event instanceof NavigationEnd),
       map((event) => event.urlAfterRedirects),
       startWith(this._router.url), // Handle initial page load
+      // Prevent dispatching setActiveWorkContext during sync - startWith() emits
+      // immediately on subscription which could interfere with sync state hydration
       skipDuringSync(),
       filter(
         (url) =>