Bring the wilm branch into main: endpoints plugin, agent, policies, CSV import

Ports the corporate-GitHub wilm branch onto main, keeping the two branches
separate. Thirteen upstream commits arrive with their authorship intact; the
review fixes and the portability work below are on top.

What arrives:

  endpoints plugin  - a ShopDB agent reporting endpoint state, telemetry,
                      services and interfaces, with a command channel the agent
                      long-polls. Ingest stays on the generic collector route
                      (ADR-006); the agent key is a UI-managed single-scope
                      token whose revocation is an instant kill switch.
  computers policies - Configuration and Business Policies (RMM-style), scope
                      trees validated at write time, actions checked against
                      the endpoints command allowlist. Feature-gated: every
                      route 404s while the setting is off, so enabling it can
                      never half-expose the surface.
  asset CSV import  - templates, a collector script carrying the site path, and
                      a validate-then-commit import. A plugin can own a virtual
                      column plus a post-write row hook, which is how a PC's
                      machine number becomes a controls link without a
                      hand-built relationships sheet.
  agent/            - the Windows agent and its installer.

Contract 0.21.0 -> 0.24.0, additive throughout: register_import_hook (0.22),
mint/list/revoke_service_token (0.23), collector_authorized (0.24). The stability
table had no rows for any of them and now does.

MySQL 5.6 portability. The branch stored three policy columns as sa.JSON, the
only JSON columns in the product, and 5.6 has no JSON type: the migration failed
with a bare syntax error near the word JSON. They are TEXT now, through a
JSONText type decorator, so all seventeen call sites still read and write dicts.
The convention elsewhere is already TEXT (guides.blocksjson,
geenforce.manifestjson).

Review fixes carried on top:

  - six policy GETs were jwt_required(optional=True), which authenticates a
    caller without checking anything; they require computers.view now, and six
    redundant jwt_required decorators are gone
  - the agent installer took a default BaseUrl and CollectorKey, so a mistyped
    run silently pointed an endpoint at the wrong instance; both are mandatory
    and a non-https BaseUrl throws unless -AllowInsecureHttp is passed
  - a committing CSV import wrote no audit row

Documentation: the 34 new routes are described in docs/api-inventory.json, which
is hand-maintained on purpose, and the generated spec now covers 331 paths and
477 operations across 22 surfaces. DEVELOPMENT-SETUP's 1071 troubleshooting row
said "use MySQL 8 for dev" and now gives the actual fix, including the trap that
5.6 downgrades ROW_FORMAT=DYNAMIC to Compact with a warning instead of an error.

Full suite 2123 passed, vitest 260 passed, all seventeen plugin chains migrate
clean on MySQL 5.6 and the naming, docs, parity and read-surface gates are green.

plugins/printers/frontend/views/PrinterForm.vue

@@ -134,7 +134,7 @@
             >
               <option value="">Select vendor...</option>
               <option
-                v-for="v in vendors"
+                v-for="v in filteredVendors"
                 :key="v.vendorid"
                 :value="v.vendorid"
               >
@@ -370,9 +370,28 @@ const vendors = ref([])
 const models = ref([])
 const locations = ref([])
 
+// Ensure a saved model id is present in models.value even when the filtered
+// list (category Printer) excluded it because it has no modeltype. Fetches the
+// single row by id and appends it; a no-op when already present or blank.
+async function ensureModelLoaded(modelId) {
+  if (!modelId) return
+  if (models.value.some(m => m.modelnumberid === modelId)) return
+  try {
+    const response = await modelsApi.get(modelId)
+    const model = response.data.data
+    if (model) models.value = [...models.value, model]
+  } catch (e) {
+    // Leave it absent; the select shows blank but we did not invent a value.
+  }
+}
+
 // Filter models by selected vendor and printer type
 const filteredModels = computed(() => {
+  const savedId = form.value.modelnumberid
   return models.value.filter(m => {
+    // Always keep the record's own saved model, so editing a printer never
+    // renders a blank select that clears the field on save.
+    if (m.modelnumberid === savedId) return true
     // Filter by vendor if selected
     if (form.value.vendorid && m.vendorid !== form.value.vendorid) {
       return false
@@ -387,6 +406,17 @@ const filteredModels = computed(() => {
   })
 })
 
+// Only offer vendors that actually have Printer-category models. models is
+// already scoped to category Printer at load, so its vendorids are the printer
+// vendor set. Keep the record's own vendor even if it falls outside that set,
+// so editing an existing printer never silently drops its saved vendor.
+const filteredVendors = computed(() => {
+  const printerVendorIds = new Set(models.value.map(m => m.vendorid))
+  return vendors.value.filter(
+    v => printerVendorIds.has(v.vendorid) || v.vendorid === form.value.vendorid
+  )
+})
+
 // Get short description from model number for naming
 function getModelShortDesc(modelNumber) {
   if (!modelNumber) return ''
@@ -493,15 +523,15 @@ onMounted(async () => {
       printersApi.types.list({ perpage: 100 }),
       assetsApi.statuses.list(),
       vendorsApi.list({ perpage: 100 }),
-      modelsApi.listAll(),
-      locationsApi.list({ perpage: 100 })
+      modelsApi.listAll({ category: 'Printer' }),
+      locationsApi.listAll()  // backend caps perpage at 100; page through all
     ])
 
     printerTypes.value = mtRes.data.data || []
     statuses.value = statusRes.data.data || []
     vendors.value = vendorRes.data.data || []
     models.value = allModels
-    locations.value = locRes.data.data || []
+    locations.value = locRes || []
 
     // Load printer if editing
     if (isEdit.value) {
@@ -539,6 +569,12 @@ onMounted(async () => {
         pin: ext.pin || ''
       }
 
+      // The model list is loaded filtered to category Printer, which the backend
+      // inner-joins against ModelType - so an untyped model is absent. If this
+      // printer's saved model is one of those rows, fetch it by id and merge it
+      // in, or its dropdown would render blank and saving would clear the field.
+      await ensureModelLoaded(form.value.modelnumberid)
+
       // Don't auto-generate for existing printers
       manualWindowsName.value = true
       manualHostname.value = true