fix: make Up to Date status persistent in skill detail page

[crossoverJie]

Problem

When clicking "Check for updates" on a skill that is already up to date, the "Up to Date" message only displayed for 2 seconds before auto-dismissing. Users could easily miss the confirmation and wouldn't know whether their skill was current.

Root Cause

SkillDetailViewModel.showUpToDate was a transient boolean flag that auto-hid after a 2-second Task.sleep. After it disappeared, the view fell back to showing the "Check for updates" button again — as if the check never happened.

Solution

Replaced the transient showUpToDate flag with the persistent skillManager.updateStatuses[skill.id] dictionary (which already stores .upToDate after a check completes). The "Up to Date" label now stays visible until the user navigates away or triggers another check.

Changes

SkillDetailViewModel.swift:

• Removed showUpToDate property
• Removed showUpToDate = true and the 2-second auto-hide Task in checkForUpdate()
• skillManager.updateStatuses[.upToDate] was already being set — no new persistence logic needed

SkillDetailView.swift:

• updateStatusView() now reads skillManager.updateStatuses[skill.id] instead of viewModel.showUpToDate
• When status is .upToDate, shows persistent green label + small "Check Again" button
• Added .upToDate case check alongside skill.hasUpdate for the update-available state

Manual Verification Required

• Open a skill detail page → click "Check for updates" → verify "Up to Date" label persists (does not disappear after 2 seconds)
• Verify the small "Check Again" button next to "Up to Date" triggers a re-check
• Verify that after re-check, the status updates correctly (either stays "Up to Date" or switches to "Update Available")
• Verify the dashboard row update status indicator still works correctly

Regression Checklist

• Skill detail page: "Check for updates" button works when status is notChecked
• Skill detail page: "Update Available" label + "Update" button still works for skills with updates
• Skill detail page: "Updating..." progress indicator still works during update
• Skill detail page: Error state still displays correctly
• Dashboard: Row-level update status indicators (green checkmark, orange dot) unchanged
• checkAllUpdates() batch check still populates updateStatuses correctly

🤖 Generated with Claude Code