chore: remove old setup-embedded migration steps

The old migration flow (detect → validate → db → groups → env →
channel-auth → channels → tasks) ran inside `bash nanoclaw.sh` via
setup/auto.ts. Replaced by the standalone `bash migrate-v2.sh` flow.

Deleted:
- setup/migrate-v1.ts (orchestrator)
- setup/migrate-v1/{detect,validate,db,env,groups,channel-auth,channels,tasks}.ts

Kept:
- setup/migrate-v1/shared.ts (used by new migrate-v2/ steps)

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

setup/auto.ts

@@ -14,10 +14,8 @@
  *                          "Terminal Agent".
  *   NANOCLAW_SKIP          comma-separated step names to skip
  *                          (environment|container|onecli|auth|mounts|
- *                           service|cli-agent|timezone|migration|channel|
+ *                           service|cli-agent|timezone|channel|
  *                           verify|first-chat)
- *   NANOCLAW_V1_PATH       explicit path to a v1 install to migrate
- *                          from (default: scan common locations)
  *
  * Timezone is auto-detected after the CLI agent step. UTC resolves are
  * confirmed with the user, and free-text replies fall through to a
@@ -41,7 +39,6 @@ import { runWhatsAppChannel } from './channels/whatsapp.js';
 import { pingCliAgent, type PingResult } from './lib/agent-ping.js';
 import { brightSelect } from './lib/bright-select.js';
 import { offerClaudeAssist } from './lib/claude-assist.js';
-import { runMigrateV1 } from './migrate-v1.js';
 import {
   applyToEnv,
   parseFlags,
@@ -437,13 +434,8 @@ async function main(): Promise<void> {
     await runTimezoneStep();
   }
 
-  if (!skip.has('migration')) {
-    // Runs silently when there's no v1 install; otherwise orchestrates the
-    // detect → validate → db → groups → env → channel-auth → channels →
-    // tasks sub-steps and writes logs/setup-migration/handoff.json for the
-    // /migrate-from-v1 skill to pick up.
-    await runMigrateV1();
-  }
+  // v1 → v2 migration is handled by `bash migrate-v2.sh`, not the setup flow.
+  // Users migrating from v1 run that script before (or instead of) setup.
 
   let channelChoice: ChannelChoice = 'skip';