feat(sync): fix exam sync pagination, add AGL/AT20-Theorie lehrgang variants with yellow checkmark

backend/src/database/migrations/097_add_lehrgang_theorie_only.sql

@@ -0,0 +1,8 @@
+-- Migration: 097_add_lehrgang_theorie_only
+-- Adds a flag to distinguish theory-only AT20 completion from full lehrgang.
+-- AT20 "mit Erfolg Theorie" = theory passed but not equipment-eligible.
+
+ALTER TABLE atemschutz_traeger
+  ADD COLUMN IF NOT EXISTS lehrgang_theorie_only BOOLEAN DEFAULT FALSE;
+
+-- The atemschutz_uebersicht view uses at.* so it picks up the new column automatically.