chore: rename remaining qwibitai/nanoclaw references to nanocoai/nanoclaw

Sweep of outbound strings, doc URLs, comments, and clone instructions
that were missed in the original org rename. One both-match case in
setup/lib/channels-remote.sh (URL detection) accepts either name so
existing forks with a `qwibitai` remote continue to resolve cleanly;
everywhere else is a straight rename.

Historical mentions left intact:
- CHANGELOG.md (v2.0.0 entry, frozen history)
- .claude/skills/add-gmail-tool/SKILL.md (pre-v2 qwibitai skill — historical)
- repo-tokens/badge.svg (auto-regenerated by update-tokens.yml)

README_ja.md

@@ -26,7 +26,7 @@ NanoClawは同じコア機能を提供しますが、理解できる規模のコ
 ## クイックスタート
 
 ```bash
-git clone https://github.com/qwibitai/nanoclaw.git nanoclaw-v2
+git clone https://github.com/nanocoai/nanoclaw.git nanoclaw-v2
 cd nanoclaw-v2
 bash nanoclaw.sh
 ```