fix(admin): resolve Low code-review findings (Admin-010,011,012)

- Admin-010: vendor Bootstrap 5.3.3 (CSS + JS bundle + maps + provenance
  README) under wwwroot/lib/bootstrap and reference local paths from
  App.razor — Admin no longer pulls Bootstrap from jsDelivr.
- Admin-011: swap FleetStatusPoller's three plain dictionaries for
  ConcurrentDictionary so ResetCache can't race a poll tick.
- Admin-012: drop the EquipmentId column from EquipmentCsvImporter (per
  admin-ui.md — equipment id is system-derived from EquipmentUuid);
  EquipmentImportBatchService and the textarea placeholder updated to
  match.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Server/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ImportEquipment.razor

@@ -79,7 +79,7 @@
         <div class="mt-3">
             <label class="form-label">CSV content (paste or uploaded)</label>
             <textarea class="form-control mono" rows="8" @bind="_csvText"
-                      placeholder="# OtOpcUaCsv v1&#10;ZTag,MachineCode,SAPID,EquipmentId,…"/>
+                      placeholder="# OtOpcUaCsv v1&#10;ZTag,MachineCode,SAPID,EquipmentUuid,Name,…"/>
         </div>
         <div class="mt-3">
             <button class="btn btn-sm btn-outline-primary" @onclick="ParseAsync" disabled="@_busy">Parse</button>