Add application support teams with contacts

Replaces the legacy supportteams/appowners pair: supportteams
(teamname unique, teamurl ServiceNow link) + supportteamcontacts
(multiple named contacts with SSO per team, the people you reach out
to), applications.supportteamid intact. Migration 7d18 migrates each
legacy team owner into a contact, drops appowners, and has a validated
downgrade. New /api/supportteams CRUD (admin writes, import-mode
timestamps, teamname lookup), Support card on application detail,
contacts column on the list, and a settings management page.
IMPORT-API.md mapping updated to the concrete endpoints.

658 tests pass; live dev migration applied (24 teams / 24 contacts);
fresh-install and downgrade round-trips verified on scratch DBs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/api/index.js

@@ -470,20 +470,36 @@ export const applicationsApi = {
   },
   updateInstalledApp(machineId, appId, data) {
     return api.put(`/applications/machines/${machineId}/${appId}`, data)
+  }
+}
+
+// Support Teams API (teams + nested contacts)
+export const supportteamsApi = {
+  list(params = {}) {
+    return api.get('/supportteams', { params })
   },
-  // Support teams
-  getSupportTeams() {
-    return api.get('/applications/supportteams')
+  get(id) {
+    return api.get(`/supportteams/${id}`)
   },
-  createSupportTeam(data) {
-    return api.post('/applications/supportteams', data)
+  create(data) {
+    return api.post('/supportteams', data)
   },
-  // App owners
-  getAppOwners() {
-    return api.get('/applications/appowners')
+  update(id, data) {
+    return api.put(`/supportteams/${id}`, data)
   },
-  createAppOwner(data) {
-    return api.post('/applications/appowners', data)
+  remove(id) {
+    return api.delete(`/supportteams/${id}`)
+  },
+  contacts: {
+    add(teamId, data) {
+      return api.post(`/supportteams/${teamId}/contacts`, data)
+    },
+    update(teamId, contactId, data) {
+      return api.put(`/supportteams/${teamId}/contacts/${contactId}`, data)
+    },
+    remove(teamId, contactId) {
+      return api.delete(`/supportteams/${teamId}/contacts/${contactId}`)
+    }
   }
 }