docs(skills): drop "v2" from skill content + src/index.ts log lines

Cleans up the prose-level v2 references that the rename commit didn't
touch. Skills now describe themselves and the codebase without "v2"
versioning language. /add-X-v2 cross-references in setup, init-first-agent,
and manage-channels updated to /add-X.

Runtime path identifiers (data/v2.db, data/v2-sessions/, container name
nanoclaw-v2) deliberately left as-is — renaming them breaks live installs
without commensurate benefit.

Verified: pnpm run build clean, 326 host tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/index.ts

@@ -1,5 +1,5 @@
 /**
- * NanoClaw v2 — main entry point.
+ * NanoClaw — main entry point.
  *
  * Thin orchestrator: init DB, run migrations, start channel adapters,
  * start delivery polls, start sweep, handle shutdown.
@@ -41,7 +41,7 @@ import type { ChannelAdapter, ChannelSetup, ConversationConfig } from './channel
 import { initChannelAdapters, teardownChannelAdapters, getChannelAdapter } from './channels/channel-registry.js';
 
 async function main(): Promise<void> {
-  log.info('NanoClaw v2 starting');
+  log.info('NanoClaw starting');
 
   // 1. Init central DB
   const dbPath = path.join(DATA_DIR, 'v2.db');
@@ -125,7 +125,7 @@ async function main(): Promise<void> {
   // 7. Start OneCLI manual-approval handler
   startOneCLIApprovalHandler(deliveryAdapter);
 
-  log.info('NanoClaw v2 running');
+  log.info('NanoClaw running');
 }
 
 /** Build ConversationConfig[] for a channel type from the central DB. */