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/skills/skill-builder/.claude-flow/metrics/task-metrics.json

@@ -0,0 +1,10 @@
+[
+  {
+    "id": "cmd-hooks-1760892801573",
+    "type": "hooks",
+    "success": true,
+    "duration": 77.53740999999997,
+    "timestamp": 1760892801651,
+    "metadata": {}
+  }
+]