Version check tooltip should have a manual "Check for Updates" button

[blinkagent]

Problem

The version check tooltip in the TitleBar currently relies on:

1. Automatic checks on app start - api.update.check() is called when the component mounts
2. Periodic background checks - every 4 hours (UPDATE_CHECK_INTERVAL_MS)
3. Hover-triggered checks - with a 1-minute cooldown (UPDATE_CHECK_HOVER_COOLDOWN_MS)

However, there's no explicit "Check for Updates" button that users can click to manually trigger a check. The current UX relies on hovering to trigger checks, which:

• Isn't obvious/discoverable to users
• Has a 1-minute cooldown that can be frustrating
• Shows "Hover to check for updates" in the idle state, which is non-standard UX

Current Behavior

From TitleBar.tsx:

• The tooltip displays "Hover to check for updates" when in idle state
• Hovering triggers handleIndicatorHover() which checks with a 1-minute cooldown
• No clickable "Check for Updates" action exists (clicking only works when an update is available/downloaded)

Proposed Solution

Add a "Check for Updates" button/link in the tooltip that users can click to manually trigger an update check, similar to most desktop applications. This would:

1. Be more discoverable than hover-based checking
2. Allow users to check on-demand without waiting for cooldowns
3. Follow standard UX patterns for update checking

References

• src/browser/components/TitleBar.tsx - lines 115-137 for hover handling, lines 143-174 for tooltip content
• src/desktop/updater.ts - checkForUpdates() method already exists and can be called via api.update.check()