chore: restore .claude commands, agents, helpers & skills (lost in 1df208d)

Restores the entire .claude/ infrastructure that was accidentally deleted
in commit 1df208d ('feat(timeline): add pulse animation for in-flight drag
mutations'). Recovered via git checkout 1df208d^.

Restored:
- .claude/commands/ (gitlooper, sparc/, github/, automation/, monitoring/,
  optimization/, hooks/, plan, implement, research, review, perf, visualaudit)
- .claude/agents/ (core/, github/, sparc/, v3/, swarm/, templates/, ...)
- .claude/helpers/ (41 scripts incl. hook-handler.cjs, statusline.cjs)
- .claude/skills/ (20 skills incl. sparc-methodology, github-*, v3-*)
- .claude/settings.json (hooks configuration)

Also updated all CapaKraken → Nexus references in affected command files.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/commands/hooks/README.md

@@ -0,0 +1,11 @@
+# Hooks Commands
+
+Commands for hooks operations in Claude Flow.
+
+## Available Commands
+
+- [pre-task](./pre-task.md)
+- [post-task](./post-task.md)
+- [pre-edit](./pre-edit.md)
+- [post-edit](./post-edit.md)
+- [session-end](./session-end.md)