Collector auto-links measuring tools for metrology PCs; settings rail cleanup

Metrology PCs (CMM, Keyence, Genspect, wax-and-trace imaging pc-types) drive
an attached measuring instrument. The PC itself stays a shopfloor PC, but the
collector now models the instrument:

- New METROLOGY_TOOL_MAP (pctypemap.py) maps those pc-types to a
  MeasuringToolType (CMM, Vision System, Genspect, Form Tracer).
- ComputersPlugin._sync_measuringtool_link creates the MeasuringTool asset
  once and a directional PC->tool "controls" relationship, tagged
  collector:measuringtool. Idempotent (re-push reuses, no duplicate asset) and
  self-archiving (a PC re-imaged to a non-metrology type deactivates the link
  but keeps the asset and any calibration history). Mirrors the printer-link
  pattern. The MeasuringToolType is created on demand if not seeded.
- 4 tests: create+link, idempotent re-push, non-metrology skip, repurpose
  archives. Non-metrology PCs never warn about a missing controls type.

Settings rail cleanup:
- Collapsible groups so the 13-group rail fits without scrolling (1511px ->
  488px). The group containing the current page expands; the rest collapse.
  CSS-drawn caret (ASCII source, no Unicode). Empty groups never render, in
  both the rail and the landing page.
- Measuring Tools group placed with the other asset groups (right after
  Machines) instead of appended last; empty placeholder positions the
  plugin-contributed cards.
- Operating Systems moved from PCs to General Reference: OS is cross-asset
  (PCs, machines, measuring tools, network devices all run one).

Plus docs/proposals/ge-enforce-plugin.md: a planning doc for refactoring
GE-Enforce/DSC into a shopdb plugin (manifest as shopdb data, payloads on
SMB/HTTP/inline), grounded in the real manifest schema.

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

frontend/src/views/settings/SettingsIndex.vue

@@ -4,7 +4,7 @@
       Pick a section from the left, or choose one below.
     </p>
 
-    <section v-for="group in groups" :key="group.title" class="landing-section">
+    <section v-for="group in visibleGroups" :key="group.title" class="landing-section">
       <h2 class="section-heading">{{ group.title }}</h2>
       <div class="landing-grid">
         <router-link
@@ -25,10 +25,15 @@
 </template>
 
 <script setup>
+import { computed } from 'vue'
 import { useSettingsCatalog } from '../../composables/settingsCatalog'
 
 // Core settings groups merged with plugin-contributed cards (ADR-010).
 const { groups } = useSettingsCatalog()
+
+// Drop empty groups (e.g. the Measuring Tools placeholder when its plugin is
+// disabled) so a bare section heading never renders.
+const visibleGroups = computed(() => groups.value.filter(g => g.cards.length))
 </script>
 
 <style scoped>

frontend/src/views/settings/SettingsLayout.vue

@@ -10,17 +10,27 @@
 
       <nav class="rail-nav">
         <template v-for="group in visibleGroups" :key="group.title">
-          <div class="rail-group-heading">{{ group.title }}</div>
-          <router-link
-            v-for="card in group.cards"
-            :key="card.to"
-            :to="card.to"
-            class="rail-link"
-            :class="{ active: isActive(card.to) }"
+          <button
+            type="button"
+            class="rail-group-heading"
+            :class="{ collapsed: !isExpanded(group.title) }"
+            @click="toggleGroup(group.title)"
           >
-            <span class="rail-icon"><component :is="card.icon" :size="16" /></span>
-            <span class="rail-label">{{ card.title }}</span>
-          </router-link>
+            <span class="rail-chevron" aria-hidden="true"></span>
+            {{ group.title }}
+          </button>
+          <template v-if="isExpanded(group.title)">
+            <router-link
+              v-for="card in group.cards"
+              :key="card.to"
+              :to="card.to"
+              class="rail-link"
+              :class="{ active: isActive(card.to) }"
+            >
+              <span class="rail-icon"><component :is="card.icon" :size="16" /></span>
+              <span class="rail-label">{{ card.title }}</span>
+            </router-link>
+          </template>
         </template>
         <p v-if="!visibleGroups.length" class="rail-empty">No matching settings</p>
       </nav>
@@ -48,7 +58,9 @@ const search = ref('')
 // Filter the rail by title/description; drop groups that end up empty.
 const visibleGroups = computed(() => {
   const term = search.value.trim().toLowerCase()
-  if (!term) return groups.value
+  // Drop empty groups (e.g. the Measuring Tools placeholder when its plugin is
+  // disabled) so a bare heading never renders.
+  if (!term) return groups.value.filter(g => g.cards.length)
   return groups.value
     .map(g => ({
       title: g.title,
@@ -65,6 +77,25 @@ function isActive(to) {
   const base = to.split('?')[0]
   return route.path === base
 }
+
+// Collapsible groups so the 13-section rail fits without scrolling: only the
+// group containing the current page is open; the user can toggle others.
+// Searching forces every matching group open.
+const groupOfActive = computed(() => {
+  for (const g of groups.value) {
+    if (g.cards.some(c => isActive(c.to))) return g.title
+  }
+  return groups.value[0]?.title
+})
+const manualToggles = ref({})
+function toggleGroup(title) {
+  manualToggles.value = { ...manualToggles.value, [title]: !isExpanded(title) }
+}
+function isExpanded(title) {
+  if (search.value.trim()) return true
+  if (title in manualToggles.value) return manualToggles.value[title]
+  return title === groupOfActive.value
+}
 </script>
 
 <style scoped>
@@ -82,11 +113,11 @@ function isActive(to) {
   overflow-y: auto;
 }
 .rail-title {
-  margin: 0 0 0.75rem 0;
-  font-size: 1.5rem;
+  margin: 0 0 0.5rem 0;
+  font-size: 1.25rem;
 }
 .rail-search {
-  margin-bottom: 0.75rem;
+  margin-bottom: 0.5rem;
 }
 .search-input {
   width: 100%;
@@ -99,26 +130,52 @@ function isActive(to) {
 }
 
 .rail-group-heading {
-  margin: 1rem 0 0.3rem 0;
+  display: flex;
+  align-items: center;
+  gap: 0.35rem;
+  width: 100%;
+  margin: 0.35rem 0 0.15rem 0;
+  padding: 0.2rem 0;
   font-size: 0.68rem;
   font-weight: 700;
   letter-spacing: 0.06em;
   text-transform: uppercase;
   color: var(--text-light);
+  background: none;
+  border: none;
+  cursor: pointer;
+  text-align: left;
+}
+.rail-group-heading:hover {
+  color: var(--text);
 }
 .rail-group-heading:first-child {
   margin-top: 0;
 }
+/* CSS-drawn caret (ASCII-only source): a right-pointing triangle that
+   rotates down when the group is expanded. */
+.rail-chevron {
+  width: 0;
+  height: 0;
+  flex: 0 0 auto;
+  border-top: 4px solid transparent;
+  border-bottom: 4px solid transparent;
+  border-left: 5px solid currentColor;
+  transition: transform 0.12s ease;
+}
+.rail-group-heading:not(.collapsed) .rail-chevron {
+  transform: rotate(90deg);
+}
 
 .rail-link {
   display: flex;
   align-items: center;
   gap: 0.5rem;
-  padding: 0.4rem 0.55rem;
+  padding: 0.25rem 0.55rem;
   border-radius: 6px;
   text-decoration: none;
   color: var(--text);
-  font-size: 0.88rem;
+  font-size: 0.86rem;
   border-left: 2px solid transparent;
 }
 .rail-link:hover {

frontend/src/views/settings/settingsNav.js

@@ -26,13 +26,15 @@ export const settingsGroups = [
       { to: '/settings/assettypes', icon: Palette, title: 'Asset Type Colors', description: 'Map colors for the top-level asset categories' },
       { to: '/settings/customfields', icon: SlidersHorizontal, title: 'Custom Fields', description: 'Define extra attributes per asset type (shown on detail + forms)' },
       { to: '/settings/supportteams', icon: Users, title: 'Support Teams', description: 'Application support teams and their contacts (ServiceNow group links)' },
+      // Operating Systems is cross-asset (PCs, machines, measuring tools, network
+      // devices all run an OS), so it lives in General Reference, not under PCs.
+      { to: '/settings/operatingsystems', icon: Cog, title: 'Operating Systems', description: 'Manage OS versions and EOL dates (used by PCs, machines, network devices, and more)' },
     ],
   },
   {
     title: 'PCs',
     cards: [
       { to: '/settings/pctypes', icon: Laptop, title: 'PC Types', description: 'Manage PC form factors + map colors' },
-      { to: '/settings/operatingsystems', icon: Cog, title: 'Operating Systems', description: 'Manage OS versions and EOL dates' },
       { to: '/settings/accessprotocols', icon: Network, title: 'PC Access Protocols', description: 'Remote-access protocols (VNC, RDP, WinRM) and link templates' },
     ],
   },
@@ -50,9 +52,16 @@ export const settingsGroups = [
       { to: '/settings/machinetypes', icon: Wrench, title: 'Machine Types', description: 'Manage machine subtypes + map colors' },
     ],
   },
-  // The "Measuring Tools" group is contributed by the measuringtools plugin via
-  // the ADR-010 get_settings_cards hook (merged in composables/settingsCatalog),
-  // not hardcoded here.
+  // The "Measuring Tools" cards are contributed by the measuringtools plugin via
+  // the ADR-010 get_settings_cards hook (merged in composables/settingsCatalog).
+  // This empty placeholder fixes the group's position among the asset groups
+  // (right after Machines); the merger fills it in place instead of appending a
+  // new group at the end. When the plugin is disabled the group stays empty and
+  // the rail/landing drop it (empty groups never render).
+  {
+    title: 'Measuring Tools',
+    cards: [],
+  },
   {
     title: 'Locations & Organization',
     cards: [