feat(tui): add unified command parser with model switching

src/frontends/tui/commands.ts

@@ -0,0 +1,85 @@
+export type Command =
+  | { type: 'quit' }
+  | { type: 'reset' }
+  | { type: 'help' }
+  | { type: 'status' }
+  | { type: 'fullscreen' }
+  | { type: 'model'; name?: string }
+  | { type: 'transfer'; target: string }
+  | { type: 'message'; content: string };
+
+export function parseCommand(input: string): Command | null {
+  const trimmed = input.trim();
+  if (!trimmed) return null;
+
+  // Quit
+  if (trimmed === '/quit' || trimmed === '/exit') {
+    return { type: 'quit' };
+  }
+
+  // Reset
+  if (trimmed === '/reset' || trimmed === '/clear') {
+    return { type: 'reset' };
+  }
+
+  // Help
+  if (trimmed === '/help' || trimmed === '/?') {
+    return { type: 'help' };
+  }
+
+  // Status
+  if (trimmed === '/status') {
+    return { type: 'status' };
+  }
+
+  // Fullscreen
+  if (trimmed === '/fullscreen' || trimmed === '/fs') {
+    return { type: 'fullscreen' };
+  }
+
+  // Model (with optional argument)
+  if (trimmed === '/model') {
+    return { type: 'model' };
+  }
+  if (trimmed.startsWith('/model ')) {
+    const name = trimmed.slice('/model '.length).trim();
+    return { type: 'model', name };
+  }
+
+  // Transfer
+  if (trimmed.startsWith('/transfer ')) {
+    const target = trimmed.slice('/transfer '.length).trim();
+    return { type: 'transfer', target };
+  }
+
+  // Regular message
+  return { type: 'message', content: trimmed };
+}
+
+export function getHelpText(): string {
+  return `
+Commands:
+  /help, /?          Show this help
+  /model [name]      Show or switch model (local, default, fast, complex)
+  /reset, /clear     Clear conversation history
+  /status            Show session info and token usage
+  /fullscreen, /fs   Switch to fullscreen mode
+  /transfer <dest>   Transfer session to another frontend
+  /quit, /exit       Exit TUI
+`.trim();
+}
+
+export type ModelAlias = 'local' | 'default' | 'fast' | 'complex' | 'opus' | 'sonnet' | 'ollama';
+
+export function resolveModelAlias(alias: string): 'local' | 'default' | 'fast' | 'complex' {
+  const map: Record<string, 'local' | 'default' | 'fast' | 'complex'> = {
+    local: 'local',
+    ollama: 'local',
+    default: 'default',
+    opus: 'default',
+    fast: 'fast',
+    sonnet: 'fast',
+    complex: 'complex',
+  };
+  return map[alias.toLowerCase()] ?? 'default';
+}