ADR-013 Phase 3: generic asset-panels renderer (Path A)

Wires the ADR-010 get_asset_panels hook to a generic frontend renderer so a
plugin adds detail-page UI as JSON, no Vue. This is the Path A foundation that
lets simple plugins ship UI without a frontend build.

- components/PluginAssetPanels.vue + pluginAssetPanels.js: fetches
  /api/pluginui/asset-panels for an asset, then each panel's data endpoint, and
  renders by mode: list (title + status badge + meta lines via a field map),
  keyvalue, table (declared or inferred columns), badge. Pure mapping logic is
  in the .js module and unit tested (9 specs), same pattern as entryForm.js.
- New 'list' render mode with a declarative field map (title/badge/meta),
  documented on the hook in base.py.
- Warranty migrated to it: get_asset_panels now declares a 'list' panel + map
  that reproduces WarrantyPanel's output (vendor title, status badge with color
  + label map, servicelevel/ends/tag meta, manage link) with zero
  warranty-specific frontend code.
- MachineDetail swapped from <WarrantyPanel> to <PluginAssetPanels> (pilot); the
  hero warranty badge is unchanged. Verified end to end: the API serves the list
  panel + map and the warranty rows; the page renders without error.

Rollout of the other 4 detail pages (PCDetail, PrinterDetail, NetworkDeviceDetail,
MeasuringToolDetail) and the map-overlays / asset-presentation renderers are
follow-up Phase 3 commits. 58 vitest, build clean, 1067 backend pass, naming green.

frontend/src/views/machines/MachineDetail.vue

@@ -204,8 +204,8 @@
           <!-- Custom Fields -->
           <CustomFieldsSection :assetid="machine.assetid" />
 
-          <!-- Warranty -->
-          <WarrantyPanel :assetid="machine.assetid" :items="warranties" />
+          <!-- Plugin-contributed detail panels (ADR-010), incl. Warranty -->
+          <PluginAssetPanels :assetid="machine.assetid" />
 
           <!-- All relationships (dualpath, controls, ...) -->
           <AssetRelationships v-if="machine.assetid" :assetid="machine.assetid" />
@@ -237,7 +237,7 @@ import { useRoute } from 'vue-router'
 import { machinesApi } from '../../api'
 import LocationMapTooltip from '../../components/LocationMapTooltip.vue'
 import CustomFieldsSection from '../../components/CustomFieldsSection.vue'
-import WarrantyPanel from '../../components/WarrantyPanel.vue'
+import PluginAssetPanels from '../../components/PluginAssetPanels.vue'
 import AssetRelationships from '../../components/AssetRelationships.vue'
 import { useWarrantyBadge } from '../../composables/warrantyBadge'
 import { useIdentifierFlags } from '../../composables/identifierSettings'
@@ -247,7 +247,7 @@ const { isEnabled } = useIdentifierFlags()
 
 const loading = ref(true)
 const machine = ref(null)
-const { warranties, heroWarranty, warrantyDate } = useWarrantyBadge(() => machine.value?.assetid)
+const { heroWarranty, warrantyDate } = useWarrantyBadge(() => machine.value?.assetid)
 
 // relationships render via the shared AssetRelationships card