Phase 7A: wire ADR-001 asset position contract surface

Lock the position-resolution columns from ADR-001 in code so
resolve_asset_position's relationship walk activates.

Schema
- Asset.mapleft -> Asset.mapx, Asset.maptop -> Asset.mapy
- Location.mapx / Location.mapy added (fallback for priority 3 of the
  ADR-001 resolution chain)
- AssetRelationship.label (free-text nuance per ADR-001)
- AssetRelationship.inheritsposition (bool, server_default true, controls
  whether the resolved-position walk follows the edge)
- RelationshipType.propagatesthroughid (self-FK; sibling-propagation rail)

Seeds
- Three canonical ADR-001 relationship types created idempotently:
  partof, controls, connectedto
- controls.propagatesthroughid wired to partof (partof + connectedto stay
  null per ADR-001 table). Both via Alembic migration AND CLI seed command
  so a fresh test fixture and a sister-site deploy both end up correct.
- Legacy connection types (Serial Cable, Direct Ethernet, USB, WiFi,
  Dualpath) retained for backward compat with pre-1.0 relationship rows.

Resolver
- shopdb.api.resolve_asset_position now walks inheritsposition=true edges
  of type partof (then controls), recursively, depth-capped at 3 with
  visited-set cycle protection. Inactive edges + non-inheritable types
  are skipped. Falls through to the existing location fallback when the
  walk yields nothing.

Tests
- 11 new test_api_namespace cases cover: partof walk, controls-after-
  partof ordering, connectedto skipped, inheritsposition=false skipped,
  recursion, cycle break, depth-3 cap, self-beats-related, related-beats-
  location, inactive-edge skip.
- 111 tests pass. Naming/style check green.

Migration
- migrations/versions/7a01_adr001_position_contract.py:
  - alter_column renames on assets (no data loss)
  - add_column on locations + relationshiptypes + assetrelationships
  - idempotent seed of three ADR types + propagation FK wire-up
  - downgrade reverses + best-effort deletion of seeded types that have
    no FK refs

Backend rename (mapleft/maptop -> mapx/mapy)
- shopdb/core/api/assets.py
- plugins/{computers,equipment,network,printers}/api/...
- scripts/migration/migrate_assets.py
- Legacy Machine model + machines API + import_from_mysql.py UNCHANGED
  (per ADR-001 Machine retires; not part of the asset contract)

Frontend rename
- frontend/src/components/ShopFloorMap.vue
- frontend/src/views/{MapEditor.vue, pcs/{PCDetail,PCForm}.vue,
  printers/{PrinterDetail,PrinterForm}.vue,
  machines/{MachineDetail,MachineForm}.vue,
  network/NetworkDeviceForm.vue}
- Form field labels + v-model bindings + computed flags switched in
  lockstep with the backend.

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

frontend/src/views/MapEditor.vue

@@ -35,8 +35,8 @@
             class="asset-item"
             :class="{
               selected: selectedAsset?.assetid === asset.assetid,
-              placed: asset.mapleft && asset.maptop,
-              unplaced: !asset.mapleft || !asset.maptop
+              placed: asset.mapx && asset.mapy,
+              unplaced: !asset.mapx || !asset.mapy
             }"
             @click="selectAsset(asset)"
           >
@@ -45,7 +45,7 @@
               <div class="asset-name">{{ asset.name || asset.assetnumber }}</div>
               <div class="asset-meta">
                 <span class="badge badge-sm">{{ asset.assettype }}</span>
-                <span v-if="asset.mapleft && asset.maptop" class="placed-indicator" title="Placed on map"><MapPin :size="12" /></span>
+                <span v-if="asset.mapx && asset.mapy" class="placed-indicator" title="Placed on map"><MapPin :size="12" /></span>
               </div>
             </div>
           </div>
@@ -75,7 +75,7 @@
             </button>
             <button
               class="btn btn-danger"
-              v-if="selectedAsset.mapleft && selectedAsset.maptop"
+              v-if="selectedAsset.mapx && selectedAsset.mapy"
               @click="clearPosition"
             >
               Remove from Map
@@ -94,7 +94,7 @@
           :assetTypeMode="true"
           :theme="currentTheme"
           :pickerMode="!!selectedAsset"
-          :initialPosition="selectedAsset ? { left: selectedAsset.mapleft, top: selectedAsset.maptop } : null"
+          :initialPosition="selectedAsset ? { left: selectedAsset.mapx, top: selectedAsset.mapy } : null"
           @positionPicked="handlePositionPicked"
           @markerClick="handleMarkerClick"
         />
@@ -125,14 +125,14 @@ const filteredAssets = computed(() => {
   }
 
   if (showUnplacedOnly.value) {
-    result = result.filter(a => !a.mapleft || !a.maptop)
+    result = result.filter(a => !a.mapx || !a.mapy)
   }
 
   return result
 })
 
 const placedAssets = computed(() => {
-  return assets.value.filter(a => a.mapleft && a.maptop)
+  return assets.value.filter(a => a.mapx && a.mapy)
 })
 
 onMounted(async () => {
@@ -163,8 +163,8 @@ function getTypeIcon(assettype) {
 
 function selectAsset(asset) {
   selectedAsset.value = asset
-  pickedPosition.value = asset.mapleft && asset.maptop
-    ? { left: asset.mapleft, top: asset.maptop }
+  pickedPosition.value = asset.mapx && asset.mapy
+    ? { left: asset.mapx, top: asset.mapy }
     : null
 }
 
@@ -181,15 +181,15 @@ async function savePosition() {
 
   try {
     await assetsApi.update(selectedAsset.value.assetid, {
-      mapleft: Math.round(pickedPosition.value.left),
-      maptop: Math.round(pickedPosition.value.top)
+      mapx: Math.round(pickedPosition.value.left),
+      mapy: Math.round(pickedPosition.value.top)
     })
 
     // Update local state
     const asset = assets.value.find(a => a.assetid === selectedAsset.value.assetid)
     if (asset) {
-      asset.mapleft = Math.round(pickedPosition.value.left)
-      asset.maptop = Math.round(pickedPosition.value.top)
+      asset.mapx = Math.round(pickedPosition.value.left)
+      asset.mapy = Math.round(pickedPosition.value.top)
     }
 
     selectedAsset.value = null
@@ -207,15 +207,15 @@ async function clearPosition() {
 
   try {
     await assetsApi.update(selectedAsset.value.assetid, {
-      mapleft: null,
-      maptop: null
+      mapx: null,
+      mapy: null
     })
 
     // Update local state
     const asset = assets.value.find(a => a.assetid === selectedAsset.value.assetid)
     if (asset) {
-      asset.mapleft = null
-      asset.maptop = null
+      asset.mapx = null
+      asset.mapy = null
     }
 
     selectedAsset.value = null