feat(setup): delete scratch agent after ping-pong, simplify flow

The "Terminal Agent" created for the connection test is now silently
deleted after a successful ping. If the user chooses to chat, a new
agent is auto-created as "{name}'s Terminal" — no name prompt needed.
Condensed the three-line ping section into a single "Connection verified."
status line.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/delete-cli-agent.ts

@@ -0,0 +1,74 @@
+/**
+ * Delete the scratch CLI agent created during setup's ping-pong test.
+ *
+ * Removes the agent group, its messaging_group_agents wiring, any
+ * agent_destinations rows, and the groups/<folder>/ directory. Leaves the
+ * CLI messaging group intact so it can be reused for a new agent.
+ *
+ * Usage:
+ *   pnpm exec tsx scripts/delete-cli-agent.ts --folder <folder-name>
+ */
+import fs from 'fs';
+import path from 'path';
+
+import { DATA_DIR } from '../src/config.js';
+import { getAgentGroupByFolder, deleteAgentGroup } from '../src/db/agent-groups.js';
+import { initDb } from '../src/db/connection.js';
+import { runMigrations } from '../src/db/migrations/index.js';
+
+interface Args {
+  folder: string;
+}
+
+function parseArgs(): Args {
+  const argv = process.argv.slice(2);
+  let folder = '';
+  for (let i = 0; i < argv.length; i++) {
+    if (argv[i] === '--folder' && argv[i + 1]) folder = argv[++i];
+  }
+  if (!folder) {
+    console.error('usage: pnpm exec tsx scripts/delete-cli-agent.ts --folder <folder-name>');
+    process.exit(1);
+  }
+  return { folder };
+}
+
+const args = parseArgs();
+
+const db = initDb(path.join(DATA_DIR, 'v2.db'));
+runMigrations(db);
+
+const ag = getAgentGroupByFolder(args.folder);
+if (!ag) {
+  console.log(`No agent group with folder "${args.folder}" — nothing to delete.`);
+  process.exit(0);
+}
+
+// Delete all rows referencing this agent group, in dependency order.
+const fkTables = [
+  'messaging_group_agents',
+  'agent_destinations',
+  'agent_group_members',
+  'pending_sender_approvals',
+  'channel_registrations',
+  'user_roles',
+  'sessions',
+];
+for (const table of fkTables) {
+  const exists = db
+    .prepare("SELECT 1 FROM sqlite_master WHERE type='table' AND name=?")
+    .get(table);
+  if (exists) {
+    db.prepare(`DELETE FROM ${table} WHERE agent_group_id = ?`).run(ag.id);
+  }
+}
+
+deleteAgentGroup(ag.id);
+
+// Remove the groups/<folder>/ directory.
+const groupDir = path.join(process.cwd(), 'groups', args.folder);
+if (fs.existsSync(groupDir)) {
+  fs.rmSync(groupDir, { recursive: true });
+}
+
+console.log(`Deleted agent group ${ag.id} (${args.folder}).`);