fix(evidence): isolate vectors by workspace

harness/scripts/create_vector_reader_rpc.sql

@@ -43,7 +43,8 @@ begin
     table_name <> 'evidence'
     or not (metadata_filter ? 'vector_generation')
     or not (metadata_filter ? 'document_ids')
-    or jsonb_object_length(metadata_filter) <> 2
+    or not (metadata_filter ? 'workspace_id')
+    or jsonb_object_length(metadata_filter) <> 3
     or jsonb_typeof(metadata_filter->'document_ids') <> 'array'
   ) then
     raise exception 'invalid Evidence metadata filter';
@@ -56,6 +57,7 @@ begin
      where ($3 is null or t.kind = any ($3))
        and ($4 is null or (
          t.metadata->>''vector_generation'' = $4->>''vector_generation''
+         and t.metadata->>''workspace_id'' = $4->>''workspace_id''
          and t.metadata->>''document_id'' in (
            select jsonb_array_elements_text($4->''document_ids'')
          )