feat(tui): add terminal user interface with Ink

Add a full TUI for Claudeman using Ink (React for CLI):
- StartScreen: Shows existing sessions from screens.json
- TabBar: Session tabs with status indicators
- TerminalView: PTY output display with scrolling
- StatusBar: Session info and keyboard shortcuts
- HelpOverlay: Full keyboard shortcut reference

Features:
- Session discovery from ~/.claudeman/screens.json
- Tab navigation (Ctrl+Tab, Ctrl+1-9)
- Create new sessions (connects to web API)
- Kill sessions via screen commands
- Keyboard-driven navigation

Usage: claudeman tui

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/tui/components/StatusBar.tsx

@@ -0,0 +1,91 @@
+/**
+ * @fileoverview StatusBar component
+ *
+ * Bottom status bar showing:
+ * - Session status (idle/working)
+ * - Token count
+ * - Cost
+ * - Runtime
+ * - Quick keyboard shortcuts
+ */
+
+import React from 'react';
+import { Box, Text } from 'ink';
+import type { ScreenSession } from '../../types.js';
+
+interface StatusBarProps {
+  session: ScreenSession | null;
+}
+
+/**
+ * Formats duration from milliseconds to human-readable string
+ */
+function formatDuration(ms: number): string {
+  const seconds = Math.floor(ms / 1000);
+  const minutes = Math.floor(seconds / 60);
+  const hours = Math.floor(minutes / 60);
+
+  if (hours > 0) {
+    return `${hours}h ${minutes % 60}m`;
+  }
+  if (minutes > 0) {
+    return `${minutes}m ${seconds % 60}s`;
+  }
+  return `${seconds}s`;
+}
+
+/**
+ * StatusBar component showing session information
+ */
+export function StatusBar({ session }: StatusBarProps): React.ReactElement {
+  if (!session) {
+    return (
+      <Box
+        borderStyle="single"
+        borderColor="gray"
+        paddingX={1}
+        justifyContent="space-between"
+      >
+        <Text dimColor>No session selected</Text>
+        <Text dimColor>Press ? for help | Esc to go back</Text>
+      </Box>
+    );
+  }
+
+  const runtime = formatDuration(Date.now() - session.createdAt);
+  const statusColor = session.attached ? 'green' : 'red';
+  const statusText = session.attached ? 'alive' : 'dead';
+
+  return (
+    <Box
+      borderStyle="single"
+      borderColor="cyan"
+      paddingX={1}
+      justifyContent="space-between"
+    >
+      {/* Left side: Session info */}
+      <Box>
+        <Text color={statusColor} bold>
+          {'\u25CF'} {statusText}
+        </Text>
+        <Text> | </Text>
+        <Text>
+          <Text dimColor>runtime:</Text> {runtime}
+        </Text>
+        <Text> | </Text>
+        <Text>
+          <Text dimColor>mode:</Text> {session.mode}
+        </Text>
+        <Text> | </Text>
+        <Text>
+          <Text dimColor>screen:</Text> {session.screenName}
+        </Text>
+      </Box>
+
+      {/* Right side: Keyboard hints */}
+      <Box>
+        <Text dimColor>? help | Esc back | Ctrl+C exit</Text>
+      </Box>
+    </Box>
+  );
+}