Add pi50 resource optimization plan, mark monitoring design complete

- New plan: Improve pi50 control plane resource usage
- Completed: Workstation monitoring design status file

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/plans/.completed/2026-01-05-workstation-monitoring-design.status

@@ -0,0 +1,17 @@
+{
+  "plan": "2026-01-05-workstation-monitoring-design.md",
+  "status": "COMPLETE",
+  "completed_at": "2026-01-05T14:09:00Z",
+  "implementation": {
+    "node_exporter": "installed and running (v1.10.2-1)",
+    "scrape_config": "deployed (workstation-scrape)",
+    "prometheus_rule": "deployed (workstation-alerts, 12 rules)",
+    "prometheus_target": "UP and scraping",
+    "git_commit": "9d17ac8",
+    "network_solution": "Tailscale (100.90.159.78:9100)"
+  },
+  "verification": {
+    "all_success_criteria_met": true,
+    "verified_at": "2026-01-05T14:09:19Z"
+  }
+}