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>

.claude/skills/add-whatsapp-cloud/SKILL.md

@@ -1,6 +1,6 @@
 ---
-name: add-whatsapp-cloud-v2
-description: Add WhatsApp Business Cloud API channel to NanoClaw v2 via Chat SDK. Official Meta API.
+name: add-whatsapp-cloud
+description: Add WhatsApp Business Cloud API channel via Chat SDK. Official Meta API.
 ---
 
 # Add WhatsApp Cloud API Channel
@@ -9,7 +9,7 @@ Connect NanoClaw to WhatsApp via the official Meta WhatsApp Business Cloud API.
 
 ## Install
 
-v2 trunk doesn't ship channels. This skill copies the WhatsApp Cloud adapter in from the `channels` branch.
+NanoClaw doesn't ship channels in trunk. This skill copies the WhatsApp Cloud adapter in from the `channels` branch.
 
 ### Pre-flight (idempotent)