fix: Clear screen on terminal resize to prevent ghost content

Added tea.ClearScreen to WindowSizeMsg handler to prevent duplicate
footer text and other ghost content when resizing the terminal. The
old view content could persist if the new view was shorter.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: GGPrompts

update.go

@@ -194,6 +194,10 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		// Reset horizontal scroll on window resize
 		m.detailScrollX = 0
 
+		// Clear screen to prevent ghost content from previous render
+		// (old content can persist if new view is shorter than old view)
+		return m, tea.ClearScreen
+
 	case tickMsg:
 		// Background refresh for git repos (every 60 seconds)
 		if m.showGitReposOnly && !m.gitReposLastScan.IsZero() {