Add Columbia integration note to help docs

Brief, user-facing mention in both the AI help knowledge base and the human
Inventory help article: the catalog is integrated with the Columbia Coatings
product catalog, refreshes near real-time, auto-fills specs/SDS/TDS, keeps
prices current for quoting, and flags discontinued powders. No API/endpoint
detail, per intent.

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

src/PowderCoating.Web/Helpers/HelpKnowledgeBase.cs

@@ -481,6 +481,8 @@ public static class HelpKnowledgeBase
         5. Enter opening quantity on hand — the system automatically records an Initial transaction for audit purposes
         6. Save
 
+        **Manufacturer catalog integration:** The platform is integrated with the Columbia Coatings product catalog. When you add a Columbia powder it auto-fills the color, specs, cure schedule, and SDS/TDS links, and keeps the price current — catalog data refreshes regularly (near real-time). Quotes use the latest catalog price even when your stored cost is older, and a powder's detail page shows the current catalog price (and flags when it has changed since you last bought it). Discontinued powders are flagged "cannot reorder" but stay usable for stock you already have.
+
         **Stock status:** Three states are shown on every item:
         - **In Stock** (green) — quantity is above the reorder point
         - **Low Stock** (red) — quantity is greater than zero but at or below the reorder point; time to reorder

src/PowderCoating.Web/Views/Help/Inventory.cshtml

@@ -138,6 +138,18 @@
                 <li class="mb-1">If a vendor name is selected in the Vendor field before searching, results are scoped to that vendor first, then broadened automatically if nothing matches.</li>
             </ul>
 
+            <div class="alert alert-permanent alert-success d-flex gap-2 mb-3" role="alert">
+                <i class="bi bi-cloud-check me-1 flex-shrink-0 mt-1"></i>
+                <div>
+                    <strong>Columbia Coatings integration:</strong> the catalog is connected directly to the Columbia Coatings
+                    product catalog and refreshes regularly (near real-time). Columbia powders auto-fill their full specs, cure
+                    schedule, and SDS/TDS links, and their prices stay current &mdash; quotes use the latest catalog price even
+                    when your stored cost is older. An item&rsquo;s detail page shows the current catalog price and flags when it
+                    has changed since you last bought it. Discontinued powders are flagged &ldquo;cannot reorder&rdquo; but stay
+                    usable for stock you already have.
+                </div>
+            </div>
+
             <h3 class="h6 fw-semibold mt-4 mb-2"><i class="bi bi-camera me-1"></i>Label Scanner (Camera)</h3>
             <p>
                 Click the <strong>camera icon</strong> next to the Lookup button to open the label scanner.