Notification system: tab-linked notifications with fade overlay and F7/F8 navigation

[JoshuaRowePhantom]

Summary

Add a notification system that allows any running code (scheduled tools, agent sessions,
background services) to post tab-linked notifications. A notification associates a tab with
a reason string. The UI shows an auto-fading overlay on new notifications and a bell toggle
button for explicit browsing.

Design

See docs/design/notifications.md.

Scope

Data model

• INotificationService.Notify(TabDescriptor tab, string? reason) — null reason clears the tab's notification
• One notification retained per tab (newest replaces oldest, marks unread)
• Snoozed tabs: auto-read, never trigger overlay popup; persisted in user-computer-profile

Overlay UI

• Anchored below the toggle button (top-right header)
• On new non-snoozed notification: appears at full opacity, fades to transparent over ~1s after 1.5s delay (unless mouse hovers)
• Toggle button: bell icon with unread count badge; opens overlay at full opacity indefinitely on click
• IsHitTestVisible = false when fully transparent

Notification row

• Tab title + reason text + relative timestamp
• Unread indicator (bold / colored dot)
• zzz button: snooze/unsnooze the tab
• Clicking row: navigate to tab, mark read, close overlay

Keyboard navigation

• F8: navigate to next (newer) unread notification; mark read
• F7: navigate to previous (older) unread notification; mark read
• Both keys reopen closed tabs using TabDescriptor

Tab navigation on click / F7/F8

• Tab open: MainWindowViewModel.OpenTabAsync
• Tab closed: reopen via TabDescriptor with original disposition

Acceptance

• Any in-process code can post/clear a notification for any tab via INotificationService
• New non-snoozed notification causes overlay to auto-show and auto-fade
• F7/F8 cycle through notifications navigating to each tab
• Snoozed tabs never trigger the overlay; their notifications are auto-read
• Null reason removes the notification for that tab

[JoshuaRowePhantom]

Update: focused-tab suppression + tab strip unread indicator

1. Active tab suppresses the notification overlay

When INotificationService.Notify is called for a tab that is currently active (i.e. documentDock.ActiveDockable corresponds to that tab), the notification is:

• Stored in the list and immediately marked IsRead = true.
• Does not trigger the auto-show overlay.

The check belongs in NotificationService.Notify, which needs to query the current active tab via a new IActiveTabProvider interface:

public interface IActiveTabProvider
{
    string? ActiveTabId { get; }
}

MainWindowViewModel implements IActiveTabProvider by reading documentDock.ActiveDockable?.Id. NotificationService receives it at construction so it can suppress the overlay when the tab is already in focus.

The updated read/unread rule table:

Event	Result
New Notify(tab, reason) — tab is active	Stored; IsRead = true; no auto-show
New Notify(tab, reason) — tab is inactive, unsnoozed	Stored; IsRead = false; auto-show triggered
Tab becomes active (user switches to it)	Any unread notification for that tab → IsRead = true; yellow border removed

2. Yellow border on tab strip for unread notifications

Tabs with an unread notification display a yellow border around the tab title text in the tab strip until the notification is marked read.

Mechanism

WorkspaceDocument (the Dock Document subclass) gains a new observable property:

public bool HasUnreadNotification
{
    get => this.hasUnreadNotification;
    set => this.SetProperty(ref this.hasUnreadNotification, value);
}

MainWindowViewModel (or a new NotificationTabBridge helper) subscribes to INotificationService.NotificationsChanged and for each WorkspaceDocument sets HasUnreadNotification to match whether there is an unread NotificationEntry for that tab's id.

Visual

The Dock tab item template (in WorkspaceDataTemplates.axaml or the Dock theme style) adds a Border around the tab title text:

<Border BorderThickness="2"
        CornerRadius="3"
        BorderBrush="{Binding HasUnreadNotification,
            Converter={StaticResource UnreadNotificationBorderBrush}}"
        Padding="2,0">
    <TextBlock Text="{Binding Title}" />
</Border>

UnreadNotificationBorderBrush converter returns Gold / #FFD700 when true, Transparent when false. No layout shift: the Border is always present with constant padding; only its BorderBrush changes.

3. Navigating to a tab marks its notification read

Any navigation that makes a tab the active dockable should call INotificationService.MarkRead(tabId):

public interface INotificationService
{
    // … existing …
    void MarkRead(string tabId);
}

This is called from MainWindowViewModel wherever SetActiveDockable / SetFocusedDockable is called — specifically in OpenTabAsync, NavigateBackCommand, NavigateForwardCommand, and any F7/F8 notification navigation. The yellow border clears immediately via HasUnreadNotification = false on the WorkspaceDocument.

Updated docs/design/notifications.md

The design doc in docs/design/notifications.md should be updated to reflect:

• The focused-tab suppression rule (§Read / unread rules table).
• IActiveTabProvider and its role in NotificationService.
• INotificationService.MarkRead(tabId) method.
• The tab strip yellow border (§Notification indicator in tab strip, new section).

[JoshuaRowePhantom]

Not a yellow border. An exclamation mark.

[JoshuaRowePhantom]

Verification passed

Checked: Commit 1ace12e (Fix #53) on the eatures branch, plus subsequent related commits. Files inspected:

• Phantom.Workspaces/Services/Notifications/INotificationService.cs, NotificationService.cs, IActiveTabProvider.cs, NotificationEntry.cs, TabDescriptor.cs, Notification.cs
• Phantom.Workspaces/ViewModels/NotificationsViewModel.cs, NotificationRowViewModel.cs, TransientPopupViewModel.cs, WorkspaceDocument.cs, MainWindowViewModel.cs
• Phantom.Workspaces/Controls/NotificationsControl.axaml, TransientPopupControl.axaml.cs
• Phantom.Workspaces/MainWindow.axaml
• Phantom.Workspaces.Gui.Shared/Styles/NotificationsStyles.axaml
• Phantom.Workspaces.Tests/NotificationServiceTests.cs, NotificationsViewModelTests.cs, NotificationRowViewModelTests.cs, AgentSessionNotificationTests.cs, TransientPopupViewModelTests.cs
• docs/design/notifications.md

Result: Implementation found, all verification criteria satisfied, tests present and green.

• ✅ INotificationService with Notify, Remove, MarkRead; one notification per tab; snoozed tabs auto-read (ephemeral in-memory by design per Bug: snoozed-notification-tabs should not be persisted on user-computer-profile; remove schema field and entity update logic #75)
• ✅ IActiveTabProvider implemented by MainWindowViewModel; active-tab suppression in NotificationService.Notify
• ✅ Overlay auto-fade (hold 2 s → 750 ms fade via TransientPopupViewModel/TransientPopupControl; hover cancels)
• ✅ Bell (🔔) toggle button with unread count badge; IsOpen popup bound two-way
• ✅ Notification row: tab title, heading/description, relative timestamp, unread exclamation (!), 💤 snooze button, click → navigate + mark read
• ✅ F7 / F8 keyboard navigation through unread notifications; MarkRead called on navigation
• ✅ WorkspaceDocument.HasUnreadNotification drives exclamation indicator in tab strip
• ✅ MarkRead called in OpenTabAsync, NavigateBackCommand, NavigateForwardCommand, F7/F8 paths
• ✅ No disabled/quarantined tests, no unresolved TODOs, no timing-dependent tests
• ⚠️ Snoozed-tab persistence (snoozed-notification-tabs schema field) was added in this commit then removed by Bug: snoozed-notification-tabs should not be persisted on user-computer-profile; remove schema field and entity update logic #75 — intentional design change, not a verification gap

Note: FakeActiveTabProvider is duplicated across NotificationServiceTests.cs and NotificationsViewModelTests.cs. Follow-up bug filed: #.

Follow-up bugs filed: see next comment

[JoshuaRowePhantom]

Follow-up bug filed: #416 — Refactor: duplicated FakeActiveTabProvider helper in notification test files