#4 fix(tui): comprehensive TUI improvements and bug fixes

Summary

Major TUI improvements including visual enhancements, bug fixes, and new features.

New Features

• Copy to Clipboard (y key): Copy selected row data (vim-style keybind)
• Export Feedback: Status messages for copy/export operations (shown in footer for 2 seconds)
• Stacked Bar Chart: Overview bars show usage breakdown by model color

Visual Improvements

• Responsive Model Column: Expands based on terminal width instead of clipping
• Sort Indicators: ▲/▼ arrows on active sort column
• Subtle Zebra Striping: Dark gray (#232328) alternating rows for readability
• Cleaner UI: Removed ugly borders from Models/Daily tabs, removed duplicate labels

Bug Fixes

• Fixed Overview Tab Selection: Blue highlight now properly follows arrow key navigation
  • Root cause: Keyboard handler only updated scrollOffset, never selectedIndex
  • Selection check scrollOffset + i === selectedIndex always failed
• Fixed Row Selection Reactivity: Blue highlight updates when navigating with ↑↓
  • Root cause: <text> elements use bg prop, not backgroundColor
  • Used createMemo inside <For> loop for proper Solid.js reactivity

Code Quality

• Removed unused ModelListItem component (inlined due to Solid.js reactivity)
• Dead code removal, edge case handling, performance optimizations
• Added keyboard modifier types to opentui.d.ts

Technical Details

• OpenTUI's <text> uses bg for background color, <box> uses backgroundColor
• Solid.js <For> requires createMemo inside callback for external signal reactivity
• Component boundaries can break reactivity when passing accessor props

Files Changed

• App.tsx - Keyboard handling, copy/export with status messages
• ModelView.tsx - Responsive columns, striping, sort cues, selection fix
• DailyView.tsx - Striping, selection fix
• OverviewView.tsx - Inline rendering for selection reactivity
• BarChart.tsx - Stacked bars with model colors
• Footer.tsx - Status message display, updated hints
• StatsView.tsx - Remove duplicate label
• index.ts - Removed unused ModelListItem export