chore: initial backup of Claude Code configuration

Includes: CLAUDE.md, settings.json, agents, commands, rules, skills,
hooks, contexts, evals, get-shit-done, plugin configs (installed list
and marketplace sources). Excludes credentials, runtime caches,
telemetry, session data, and plugin binary cache.

commands/gsd/join-discord.md

@@ -0,0 +1,18 @@
+---
+name: gsd:join-discord
+description: Join the GSD Discord community
+---
+
+<objective>
+Display the Discord invite link for the GSD community server.
+</objective>
+
+<output>
+# Join the GSD Discord
+
+Connect with other GSD users, get help, share what you're building, and stay updated.
+
+**Invite link:** https://discord.gg/gsd
+
+Click the link or paste it into your browser to join.
+</output>