chore(skills): add /publish slash command + allow .claude/ in git

Mirrors the slash command added in torrentclaw-web/.claude/commands.
With the global ~/.gitignore excluding .claude/ by default, the
gitignore override is required for project-shared commands/agents/hooks
to be checked in (settings.local.json and projects/ stay local).

/publish documents the full unarr release flow (bump + tag + binaries +
Hetzner + Docker Hub + smoke) as a single command, while GitHub Actions
remains unavailable for the torrentclaw org.

.gitignore

@@ -42,3 +42,19 @@ dist-ffbinaries/
 tmp/
 config/
 dist-ffbinaries/
+
+# Claude Code: global ~/.gitignore excludes .claude/ by default, which hides
+# project-shared agents/commands/hooks. Override here to commit the shared
+# pieces (agents, commands, hooks, settings.json). Keep per-user state local.
+!.claude/
+!.claude/agents/
+!.claude/agents/**
+!.claude/commands/
+!.claude/commands/**
+!.claude/hooks/
+!.claude/hooks/**
+!.claude/settings.json
+.claude/settings.local.json
+.claude/projects/
+.claude/scheduled_tasks.lock
+.claude/skills/