GE-Enforce polish: DDL-parity guard test, retire Collector PC Types page

Add test_geenforce_ddl_parity to lock the manifest models against their
Alembic baseline (catches model/migration drift for a chain that is still
amendable pre-deploy).

Retire the "Collector PC Types" settings card: GE-Enforce scope
computertypeid supersedes the pctypemap editor UI (ADR-012). The collector
still reads pctype_mapping(), so the backend map stays; only the editor
surface is removed, with a deprecation note in pctypemap.py.

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

plugins/computers/pctypemap.py

@@ -23,6 +23,9 @@ DEFAULT_PCTYPE_MAP = {
     'gea-shopfloor-partmarker': 'Shopfloor PC',
 }
 
+# DEPRECATED settings surface: the "Collector PC Types" settings page is retired
+# (GE-Enforce scope computertypeid supersedes it, ADR-012). Collector still reads
+# this map, so keep the code; only the editor UI card is gone.
 _SETTING_PREFIX = 'pctypemap_'
 _SETTING_CATEGORY = 'pctypemapping'