Set up document management for Stirling Engine (#6476)

# Description of Changes
Change Stirling Engine to support deleting documents automatically. This
happens both on user logout and after an amount of time specified by the
Java when ingesting a document (allowing for personal documents to have
short lifetimes but org documents to be left in the db with no expiry
date). Also sets up an [ACL
policy](https://en.wikipedia.org/wiki/Access-control_list) for the
documents so the database knows which users have access to which
documents. This is not fully implemented in the Java, so currently all
docs are treated as having a single owner, the uploader, but
theoretically when we need to support org storage, we shouldn't need to
change the db schema.

engine/src/stirling/agents/shared/whole_doc_reader.py

@@ -19,6 +19,7 @@ from pydantic_ai.toolsets import AbstractToolset
 
 from stirling.agents.shared.chunked_reasoner import ChunkedReasoner
 from stirling.contracts import AiFile
+from stirling.models import PrincipalId
 from stirling.services import AppRuntime
 
 logger = logging.getLogger(__name__)
@@ -47,12 +48,14 @@ class WholeDocReaderCapability:
         self,
         runtime: AppRuntime,
         files: list[AiFile],
+        principals: list[PrincipalId],
         *,
         reasoner: ChunkedReasoner | None = None,
         max_reads: int = DEFAULT_MAX_READS,
     ) -> None:
         self._runtime = runtime
         self._files = files
+        self._principals = principals
         self._reasoner = reasoner if reasoner is not None else ChunkedReasoner(runtime)
         self._max_reads = max_reads
         self._read_count = 0
@@ -115,7 +118,7 @@ class WholeDocReaderCapability:
 
         sections: list[str] = []
         for file in self._files:
-            pages = await self._runtime.documents.read_pages(file.id)
+            pages = await self._runtime.documents.read_pages(file.id, principals=self._principals)
             if not pages:
                 logger.info(
                     "[whole-doc-reader] no stored pages for %s (id=%s); skipping",