feat(admin): plan statistics + node restart/close-ae actions

Final legacy-admin items:
- identity GET /v1/admin/plan-statistics (active/total users + revenue per plan
  from user_plans); surfaced as a breakdown table in /admin/stats
- NodesTable: wire Restart + Close-AE actions (backend already supported them) via
  new proxy routes; was only drain/release before

Full DivineGateWeb legacy-admin parity achieved.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/identity/FlatRender.IdentitySvc/Controllers/AdminController.cs

@@ -22,6 +22,10 @@ public class AdminController(AdminService svc) : ControllerBase
         return Ok(await svc.GetCrmAnalyticsAsync(TenantId, s, e));
     }
 
+    // ── Plan statistics ──────────────────────────────────────────────────────
+    [HttpGet("v1/admin/plan-statistics")]
+    public async Task<IActionResult> PlanStats() => Ok(await svc.GetPlanStatisticsAsync(TenantId));
+
     // ── CRM notes / tags ───────────────────────────────────────────────────────
     [HttpGet("v1/users/{userId:guid}/crm")]
     public async Task<IActionResult> GetCrm(Guid userId) => Ok(await svc.GetUserCrmAsync(userId));