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>

shopdb/__init__.py

@@ -114,6 +114,7 @@ CORE_BLUEPRINT_NAMES = (
     'dashboard',
     'dashboarddefaults',
     'applications',
+    'supportteams',
     'search',
     'reports',
     'collector',