refactor(server): indexer & worker & sync perf (#15504)

packages/backend/server/migrations/20260820120000_cleanup_legacy_copilot_runtime/migration.sql

@@ -0,0 +1,46 @@
+-- This migration is intentionally fail-closed. The data migration with the
+-- same release must have admitted every live legacy context blob through the
+-- artifact runtime before these product-owned tables are removed.
+DO $$
+BEGIN
+  IF to_regclass('public.ai_contexts') IS NOT NULL AND EXISTS (
+    SELECT 1
+    FROM ai_contexts context
+    JOIN ai_sessions_metadata session ON session.id = context.session_id
+    JOIN blobs blob
+      ON blob.workspace_id = session.workspace_id
+     AND blob.deleted_at IS NULL
+     AND blob.status = 'completed'
+    WHERE jsonb_path_exists(
+      context.config::jsonb,
+      '$.** ? (@ == $blobKey)',
+      jsonb_build_object('blobKey', to_jsonb(blob.key::text))
+      )
+      AND NOT EXISTS (
+        SELECT 1
+        FROM workspace_artifacts artifact
+        WHERE artifact.workspace_id = session.workspace_id
+          AND artifact.status = 'ready'
+          AND artifact.storage_scope = 'blob'
+          AND artifact.storage_key = concat(session.workspace_id, '/', blob.key)
+      )
+  ) THEN
+    RAISE EXCEPTION
+      'legacy context blob artifact admission is incomplete; run the data migration before cleanup';
+  END IF;
+END $$;
+
+DELETE FROM app_configs WHERE id = 'copilot.providers.defaults';
+
+ALTER TABLE ai_workspace_byok_configs
+  ALTER COLUMN definition DROP DEFAULT,
+  DROP COLUMN IF EXISTS endpoint,
+  DROP COLUMN IF EXISTS disabled_reason,
+  DROP COLUMN IF EXISTS last_validated_at,
+  DROP COLUMN IF EXISTS last_validation_error;
+
+DELETE FROM ai_workspace_byok_configs WHERE definition = '{}'::jsonb;
+
+DROP TABLE IF EXISTS ai_context_embeddings;
+DROP TABLE IF EXISTS ai_workspace_embeddings;
+DROP TABLE IF EXISTS ai_contexts;