Merged in feature/chatbot1 (pull request #223)

Chatbot functionality

* baseline working

* missing test file

* more tests

internal/database/queries/document.sql

@@ -81,6 +81,29 @@ SELECT
 FROM documents d
 WHERE d.id = $1;
 
+-- name: GetDocumentEnrichedForClient :one
+-- Chatbot-scoped read: same column set as GetDocumentEnriched, but adds a
+-- clientId filter so cross-client lookups miss with pgx.ErrNoRows.
+-- Plan §5 mandates a clientId filter on every chatbot document/folder
+-- read so document scope cannot leak between clients. documents.clientId
+-- is the unquoted (lowercased) varchar column from migration 5.
+SELECT
+    d.id,
+    d.clientId,
+    d.hash,
+    d.folderId,
+    d.filename,
+    d.originalPath,
+    d.file_size_bytes,
+    d.custom_schema_id,
+    EXISTS(
+        SELECT 1 FROM document_custom_metadata
+        WHERE document_id = d.id
+    ) AS has_custom_metadata
+FROM documents d
+WHERE d.id = @id
+  AND d.clientId = @client_id;
+
 -- name: LockDocumentForLegacyExtractionWrite :one
 -- Milestone 2.5 parent-row lock acquired by CreateFieldExtraction as the
 -- FIRST DML statement inside its transaction. Serializes with AssignSchema