Bulk Dell warranty sync + add-warranty from asset pages

- POST /warranty/sync/dell: auto-detect Dell hardware by service tag (asset
  serial) and create warranties for the ones Dell recognizes, in batches of 100.
  Only looks up assets that lack a dated warranty, so re-runs are cheap and
  non-Dell serials are filtered out by Dell. DellProvider.bulk_lookup batches
  tags over the cached token.
- "Sync Dell" button on the Warranties page with a toast summary.
- WarrantyPanel "Add one / Add-manage" links deep-link to the warranties add
  modal pre-linked to that asset (?addfor=); WarrantiesList opens it prefilled.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plugins/warranty/api/routes.py

@@ -210,6 +210,95 @@ def refresh_warranty(warrantyid):
     return success_response(_warranty_payload(warranty), message='Warranty refreshed')
 
 
+# =============================================================================
+# Bulk Dell sync - auto-detect Dell hardware by service tag and pull coverage
+# =============================================================================
+
+@warranty_bp.route('/sync/dell', methods=['POST'])
+@jwt_required()
+@require_permission('warranty.edit')
+def sync_dell():
+    """Look up every asset serial (= Dell service tag) that has no warranty yet
+    and create warranties for the ones Dell recognizes.
+
+    Only assets that lack a dated warranty are looked up, so re-running is cheap
+    and non-Dell serials are filtered out by Dell (they return no coverage).
+    """
+    provider = get_provider('dell')
+
+    # Assets already covered by a dated warranty - skip these.
+    covered = set()
+    for link in WarrantyAsset.query.all():
+        w = Warranty.query.get(link.warrantyid)
+        if w and w.isactive and w.enddate:
+            covered.add(link.assetid)
+
+    # Candidate assets: active, have a serial, not already covered.
+    candidates = (Asset.query
+                  .filter(Asset.isactive.is_(True),
+                          Asset.serialnumber.isnot(None),
+                          Asset.serialnumber != '')
+                  .all())
+    by_tag = {}
+    for asset in candidates:
+        if asset.assetid in covered:
+            continue
+        by_tag.setdefault(asset.serialnumber.strip().upper(), []).append(asset.assetid)
+
+    if not by_tag:
+        return success_response({
+            'candidates': 0, 'matched': 0, 'created': 0, 'updated': 0,
+        }, message='No PCs need a warranty lookup.')
+
+    try:
+        results = provider.bulk_lookup(list(by_tag.keys()))
+    except (ProviderNotConfigured, WarrantyLookupError) as exc:
+        return error_response(ErrorCodes.VALIDATION_ERROR, str(exc), http_code=400)
+
+    created = updated = matched = 0
+    now = datetime.utcnow()
+    for tag, assetids in by_tag.items():
+        found = results.get(tag)
+        if not found:
+            continue
+        matched += 1
+        for assetid in assetids:
+            # Reuse an existing Dell warranty for this asset if there is one.
+            existing = None
+            for link in WarrantyAsset.query.filter_by(assetid=assetid).all():
+                candidate = Warranty.query.get(link.warrantyid)
+                if candidate and candidate.provider == 'dell':
+                    existing = candidate
+                    break
+            if existing:
+                existing.servicelevel = found.get('servicelevel')
+                existing.startdate = _parse_date(found.get('startdate'))
+                existing.enddate = _parse_date(found.get('enddate'))
+                existing.servicetag = tag
+                existing.lastcheckeddate = now
+                updated += 1
+            else:
+                warranty = Warranty(
+                    vendor='Dell', provider='dell', servicetag=tag,
+                    servicelevel=found.get('servicelevel'),
+                    startdate=_parse_date(found.get('startdate')),
+                    enddate=_parse_date(found.get('enddate')),
+                    lastcheckeddate=now,
+                )
+                warranty.links.append(WarrantyAsset(assetid=assetid))
+                db.session.add(warranty)
+                created += 1
+
+    db.session.commit()
+    return success_response({
+        'candidates': sum(len(v) for v in by_tag.values()),
+        'tags': len(by_tag),
+        'matched': matched,
+        'created': created,
+        'updated': updated,
+    }, message=f'Dell sync: {created} added, {updated} updated, {matched} tags matched.')
+
+
 # =============================================================================
 # Report buckets (for the Reports hub)
 # =============================================================================