Replace Log Material item dropdown with searchable combobox

Inventory lists grow over time; a plain <select> becomes unusable. The
new combobox filters as you type, supports keyboard navigation
(Arrow/Enter/Escape), and shows current stock on selection — matching
the pattern used by the powder picker in the item wizard.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Views/Jobs/Details.cshtml

@@ -1105,9 +1105,22 @@
                             <div class="modal-body">
                                 <div class="mb-3">
                                     <label class="form-label fw-semibold">Inventory Item <span class="text-danger">*</span></label>
-                                    <select id="lmInventoryItem" class="form-select">
-                                        <option value="">-- Select item --</option>
-                                    </select>
+                                    <div class="position-relative">
+                                        <div class="input-group">
+                                            <input type="text" class="form-control" id="lmItemSearch"
+                                                   placeholder="Search by name or unit&hellip;" autocomplete="off"
+                                                   oninput="lmComboInput()"
+                                                   onfocus="lmComboOpen()"
+                                                   onkeydown="lmComboKey(event)">
+                                            <button class="btn btn-outline-secondary" type="button" tabindex="-1"
+                                                    id="lmItemDropdownToggle" onclick="lmComboToggle()">
+                                                <i class="bi bi-chevron-down" style="font-size:.75rem;"></i>
+                                            </button>
+                                        </div>
+                                        <div id="lmItemDropdown"
+                                             style="display:none;max-height:220px;overflow-y:auto;z-index:1070;background:#fff;border:1px solid rgba(0,0,0,.15);border-radius:.375rem;box-shadow:0 4px 12px rgba(0,0,0,.12);">
+                                        </div>
+                                    </div>
                                     <div id="lmItemBalance" class="form-text text-muted d-none"></div>
                                 </div>
                                 <div class="mb-3">