feat(cli): TUI slash command parsing + local commands (P8-009) (#176)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/cli/src/tui/commands/registry.ts

@@ -0,0 +1,98 @@
+import type { CommandDef, CommandManifest } from '@mosaic/types';
+
+// Local-only commands (work even when gateway is disconnected)
+const LOCAL_COMMANDS: CommandDef[] = [
+  {
+    name: 'help',
+    description: 'Show available commands',
+    aliases: ['h'],
+    args: undefined,
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
+  {
+    name: 'stop',
+    description: 'Cancel current streaming response',
+    aliases: [],
+    args: undefined,
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
+  {
+    name: 'cost',
+    description: 'Show token usage and cost for current session',
+    aliases: [],
+    args: undefined,
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
+  {
+    name: 'status',
+    description: 'Show connection and session status',
+    aliases: ['s'],
+    args: undefined,
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
+  {
+    name: 'clear',
+    description: 'Clear the current conversation display',
+    aliases: [],
+    args: undefined,
+    execution: 'local',
+    available: true,
+    scope: 'core',
+  },
+];
+
+const ALIASES: Record<string, string> = {
+  n: 'new',
+  m: 'model',
+  t: 'thinking',
+  a: 'agent',
+  s: 'status',
+  h: 'help',
+  pref: 'preferences',
+};
+
+export class CommandRegistry {
+  private gatewayManifest: CommandManifest | null = null;
+
+  updateManifest(manifest: CommandManifest): void {
+    this.gatewayManifest = manifest;
+  }
+
+  resolveAlias(command: string): string {
+    return ALIASES[command] ?? command;
+  }
+
+  find(command: string): CommandDef | null {
+    const resolved = this.resolveAlias(command);
+    // Search local first, then gateway manifest
+    const local = LOCAL_COMMANDS.find((c) => c.name === resolved || c.aliases.includes(resolved));
+    if (local) return local;
+    if (this.gatewayManifest) {
+      return (
+        this.gatewayManifest.commands.find(
+          (c) => c.name === resolved || c.aliases.includes(resolved),
+        ) ?? null
+      );
+    }
+    return null;
+  }
+
+  getAll(): CommandDef[] {
+    const gateway = this.gatewayManifest?.commands ?? [];
+    return [...LOCAL_COMMANDS, ...gateway];
+  }
+
+  getLocalCommands(): CommandDef[] {
+    return LOCAL_COMMANDS;
+  }
+}
+
+export const commandRegistry = new CommandRegistry();