test(platform): Add tests for document_list and document_retrieve tools

[larryro]

Summary

Add comprehensive unit and integration tests for the document_list (#658) and document_retrieve (#659) agent tools.

Test Coverage

document_list tool

• Happy paths: list all documents, filter by folder, filter by extension, filter by date range, combined filters
• Sorting: sort by createdAt desc (default), sort by name asc
• Pagination: limit parameter, hasMore flag, totalCount accuracy
• Access control: only returns documents matching user's organizationId and teamTags
• Edge cases: empty results, no matching filters, limit=0, invalid date format

document_retrieve tool

• Happy paths: retrieve full document content, retrieve with pageRange
• Pagination: pageRange="1-5", pageRange="20-30", single page pageRange="5-5"
• Truncation: document exceeding ~50K chars returns truncated=true
• Access control: rejects requests for documents outside user's organization/team
• Error cases: non-existent documentId (404), document without RAG info, invalid pageRange format
• Integration with RAG service: mock RAG endpoint, verify correct parameters passed

Dependencies

• Depends on feat(platform): Add document_list agent tool #658 (document_list tool)
• Depends on feat(platform): Add document_retrieve agent tool with pagination #659 (document_retrieve tool)

Acceptance Criteria

• All happy path tests pass
• Access control tests verify organization and team scoping
• Edge case and error condition tests pass
• Tests follow existing patterns (reference: services/platform/convex/workflow_engine/ test files)