feat(admin): add five-identifier ranked equipment search (Phase 6.4 Stream B.5)

Implements the missing Stream B.5 search from the Phase 6.4 plan:
- EquipmentService.SearchAsync scopes to a cluster, scores hits across
  ZTag / MachineCode / SAPID / EquipmentId / EquipmentUuid (decision #117):
  exact = 100, prefix = 50, fuzzy (opt-in) = 20; published generation
  outranks draft on equal scores per spec.
- EquipmentSearchHit record carries Score + MatchedField for badge display.
- EquipmentTab.razor gains a search panel with per-row matched-field chips
  (green exact, amber prefix, grey fuzzy) and fuzzy opt-in checkbox.
- 14 new unit tests in EquipmentSearchTests.cs (Category=Unit) cover exact,
  prefix, fuzzy, case-insensitivity, tie-break, cross-cluster isolation, and
  maxResults cap; all 148 admin unit tests pass.

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

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

@@ -12,6 +12,98 @@
     </div>
 </div>
 
+@* Five-identifier search — decision #117: ZTag / MachineCode / SAPID / EquipmentId / EquipmentUuid *@
+<section class="panel rise mb-3" style="animation-delay:.02s">
+    <div class="panel-head">Search equipment</div>
+    <div class="p-3">
+        <div class="row g-2 align-items-end">
+            <div class="col-md-6">
+                <label class="form-label small mb-1">
+                    Search by ZTag, MachineCode, SAPID, EquipmentId, or EquipmentUuid
+                </label>
+                <input class="form-control form-control-sm"
+                       placeholder="e.g. z-001 or MC-42 or SAP-…"
+                       @bind="_searchQuery"
+                       @bind:event="oninput"
+                       @onkeydown="OnSearchKeyDown"/>
+            </div>
+            <div class="col-auto">
+                <div class="form-check form-check-inline mb-0">
+                    <input class="form-check-input" type="checkbox" id="fuzzyCheck" @bind="_searchFuzzy"/>
+                    <label class="form-check-label small" for="fuzzyCheck">Fuzzy (substring)</label>
+                </div>
+            </div>
+            <div class="col-auto">
+                <button class="btn btn-sm btn-outline-secondary" @onclick="RunSearchAsync" disabled="@_searchBusy">Search</button>
+                @if (_searchHits is not null)
+                {
+                    <button class="btn btn-sm btn-link ms-1" @onclick="ClearSearch">Clear</button>
+                }
+            </div>
+        </div>
+        @if (_searchError is not null)
+        {
+            <p class="small text-danger mt-2 mb-0">@_searchError</p>
+        }
+    </div>
+
+    @if (_searchHits is not null)
+    {
+        @if (_searchHits.Count == 0)
+        {
+            <p class="p-3 text-muted small mb-0">No matches.</p>
+        }
+        else
+        {
+            <div class="table-wrap" style="max-height: 340px; overflow-y: auto;">
+                <table class="data-table">
+                    <thead>
+                        <tr>
+                            <th>EquipmentId</th><th>Name</th><th>MachineCode</th><th>ZTag</th><th>SAPID</th>
+                            <th style="width:110px">Matched</th><th style="width:80px">Gen</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                    @foreach (var hit in _searchHits)
+                    {
+                        <tr>
+                            <td><span class="mono">@hit.Equipment.EquipmentId</span></td>
+                            <td>@hit.Equipment.Name</td>
+                            <td>@hit.Equipment.MachineCode</td>
+                            <td>@hit.Equipment.ZTag</td>
+                            <td>@hit.Equipment.SAPID</td>
+                            <td>
+                                @if (hit.MatchedField is not null)
+                                {
+                                    var chipClass = hit.Score switch
+                                    {
+                                        100 => "chip chip-ok",
+                                        50  => "chip chip-warn",
+                                        _   => "chip chip-idle",
+                                    };
+                                    <span class="@chipClass">@hit.MatchedField</span>
+                                }
+                            </td>
+                            <td>
+                                @if (hit.IsPublished)
+                                { <span class="chip chip-ok">pub</span> }
+                                else
+                                { <span class="chip chip-idle">draft</span> }
+                            </td>
+                        </tr>
+                    }
+                    </tbody>
+                </table>
+            </div>
+            <p class="p-2 text-muted small mb-0">
+                @_searchHits.Count result@(_searchHits.Count == 1 ? "" : "s").
+                Exact = green, prefix = amber, fuzzy = grey.
+                Fuzzy matching requires the "Fuzzy" checkbox.
+            </p>
+        }
+    }
+</section>
+
 @if (_equipment is null)
 {
     <p>Loading…</p>
@@ -114,6 +206,41 @@ else if (_equipment.Count > 0)
     private Equipment _draft = NewBlankDraft();
     private string? _error;
 
+    // ── Five-identifier search ──────────────────────────────────────────
+    private string _searchQuery = string.Empty;
+    private bool _searchFuzzy;
+    private IReadOnlyList<EquipmentSearchHit>? _searchHits;
+    private bool _searchBusy;
+    private string? _searchError;
+
+    private async Task RunSearchAsync()
+    {
+        _searchError = null;
+        if (string.IsNullOrWhiteSpace(_searchQuery)) { _searchHits = null; return; }
+        _searchBusy = true;
+        try
+        {
+            _searchHits = await EquipmentSvc.SearchAsync(
+                _searchQuery, ClusterId, CancellationToken.None,
+                maxResults: 50, allowFuzzy: _searchFuzzy);
+        }
+        catch (Exception ex) { _searchError = ex.Message; }
+        finally { _searchBusy = false; }
+    }
+
+    private void ClearSearch()
+    {
+        _searchQuery = string.Empty;
+        _searchHits = null;
+        _searchError = null;
+    }
+
+    private async Task OnSearchKeyDown(KeyboardEventArgs e)
+    {
+        if (e.Key == "Enter") await RunSearchAsync();
+    }
+    // ───────────────────────────────────────────────────────────────────
+
     private static Equipment NewBlankDraft() => new()
     {
         EquipmentId = string.Empty, DriverInstanceId = string.Empty,