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/App.tsx

@@ -0,0 +1,215 @@
+/**
+ * @fileoverview Main TUI App component
+ *
+ * The root component that manages the overall TUI layout:
+ * - StartScreen: Initial session discovery view
+ * - Main view: TabBar + Terminal + StatusBar
+ */
+
+import React, { useState, useEffect, useCallback } from 'react';
+import { Box, Text, useApp, useInput, useStdout } from 'ink';
+import { StartScreen } from './components/StartScreen.js';
+import { TabBar } from './components/TabBar.js';
+import { TerminalView } from './components/TerminalView.js';
+import { StatusBar } from './components/StatusBar.js';
+import { HelpOverlay } from './components/HelpOverlay.js';
+import { useSessionManager } from './hooks/useSessionManager.js';
+import type { ScreenSession } from '../types.js';
+
+type ViewMode = 'start' | 'main';
+
+/**
+ * Main application component
+ */
+export function App(): React.ReactElement {
+  const { exit } = useApp();
+  const { stdout } = useStdout();
+  const [viewMode, setViewMode] = useState<ViewMode>('start');
+  const [showHelp, setShowHelp] = useState(false);
+  const [terminalHeight, setTerminalHeight] = useState(20);
+
+  const {
+    sessions,
+    activeSessionId,
+    activeSession,
+    refreshSessions,
+    selectSession,
+    createSession,
+    killSession,
+    killAllSessions,
+    nextSession,
+    prevSession,
+    sendInput,
+    terminalOutput,
+  } = useSessionManager();
+
+  // Calculate terminal height based on stdout dimensions
+  useEffect(() => {
+    const updateHeight = () => {
+      // Reserve: 3 for TabBar, 3 for StatusBar, 2 for borders
+      const rows = stdout?.rows || 24;
+      setTerminalHeight(Math.max(10, rows - 8));
+    };
+    updateHeight();
+
+    stdout?.on('resize', updateHeight);
+    return () => {
+      stdout?.off('resize', updateHeight);
+    };
+  }, [stdout]);
+
+  // Handle keyboard input
+  useInput((input, key) => {
+    // Help overlay takes priority
+    if (showHelp) {
+      if (key.escape || input === 'q' || input === '?') {
+        setShowHelp(false);
+      }
+      return;
+    }
+
+    // Global shortcuts
+    if (input === '?' || (key.ctrl && input === 'h')) {
+      setShowHelp(true);
+      return;
+    }
+
+    // Exit on Ctrl+C (with confirmation in main view)
+    if (key.ctrl && input === 'c') {
+      exit();
+      return;
+    }
+
+    // Start screen specific inputs
+    if (viewMode === 'start') {
+      if (input === 'q') {
+        exit();
+        return;
+      }
+      if (input === 'n') {
+        handleCreateSession();
+        return;
+      }
+      if (input === 'r') {
+        refreshSessions();
+        return;
+      }
+      // Number keys to select session
+      const num = parseInt(input, 10);
+      if (!isNaN(num) && num >= 1 && num <= sessions.length) {
+        handleSelectSession(sessions[num - 1]);
+        return;
+      }
+      return;
+    }
+
+    // Main view shortcuts
+    if (key.ctrl && key.tab) {
+      if (key.shift) {
+        prevSession();
+      } else {
+        nextSession();
+      }
+      return;
+    }
+
+    // Ctrl+1-9 for direct tab access
+    if (key.ctrl) {
+      const num = parseInt(input, 10);
+      if (!isNaN(num) && num >= 1 && num <= 9 && num <= sessions.length) {
+        selectSession(sessions[num - 1].sessionId);
+        return;
+      }
+    }
+
+    // Ctrl+W to close current session
+    if (key.ctrl && input === 'w') {
+      if (activeSessionId) {
+        killSession(activeSessionId);
+        if (sessions.length <= 1) {
+          setViewMode('start');
+        }
+      }
+      return;
+    }
+
+    // Ctrl+K to kill all sessions
+    if (key.ctrl && input === 'k') {
+      killAllSessions();
+      setViewMode('start');
+      return;
+    }
+
+    // Ctrl+N for new session
+    if (key.ctrl && input === 'n') {
+      handleCreateSession();
+      return;
+    }
+
+    // Escape to go back to start screen
+    if (key.escape) {
+      setViewMode('start');
+      return;
+    }
+
+    // Forward other input to the active session
+    if (activeSessionId && !key.ctrl && !key.meta) {
+      if (key.return) {
+        sendInput(activeSessionId, '\r');
+      } else if (key.backspace || key.delete) {
+        sendInput(activeSessionId, '\x7f');
+      } else if (input) {
+        sendInput(activeSessionId, input);
+      }
+    }
+  });
+
+  const handleSelectSession = useCallback((session: ScreenSession) => {
+    selectSession(session.sessionId);
+    setViewMode('main');
+  }, [selectSession]);
+
+  const handleCreateSession = useCallback(async () => {
+    const sessionId = await createSession();
+    if (sessionId) {
+      setViewMode('main');
+    }
+  }, [createSession]);
+
+  // Render help overlay if shown
+  if (showHelp) {
+    return <HelpOverlay onClose={() => setShowHelp(false)} />;
+  }
+
+  // Render start screen
+  if (viewMode === 'start') {
+    return (
+      <StartScreen
+        sessions={sessions}
+        onSelectSession={handleSelectSession}
+        onCreateSession={handleCreateSession}
+        onRefresh={refreshSessions}
+        onExit={exit}
+      />
+    );
+  }
+
+  // Render main view with tabs, terminal, and status bar
+  return (
+    <Box flexDirection="column" height="100%">
+      <TabBar
+        sessions={sessions}
+        activeSessionId={activeSessionId}
+        onSelectSession={(id) => selectSession(id)}
+      />
+
+      <TerminalView
+        output={terminalOutput}
+        height={terminalHeight}
+        session={activeSession}
+      />
+
+      <StatusBar session={activeSession} />
+    </Box>
+  );
+}