Add bridge backend for sync

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/coredata/migrations/20260129T120000Z.sql

@@ -0,0 +1,7 @@
+-- Add sync tracking fields to iam_scim_bridges table
+ALTER TABLE iam_scim_bridges ADD COLUMN last_synced_at TIMESTAMP WITH TIME ZONE;
+ALTER TABLE iam_scim_bridges ADD COLUMN next_sync_at TIMESTAMP WITH TIME ZONE DEFAULT NOW();
+ALTER TABLE iam_scim_bridges ADD COLUMN sync_error TEXT;
+
+-- Create index for efficient polling of bridges due for sync
+CREATE INDEX idx_iam_scim_bridges_next_sync ON iam_scim_bridges (next_sync_at) WHERE state = 'ACTIVE';