feat(mcp): add document inbox tools and PDF transfers

backend/tests/mcpPagination.test.ts

@@ -10,7 +10,8 @@ const tables = Object.values(schema).filter((value: any) => {
     try { return typeof getTableName(value) === "string" } catch { return false }
 })
 
-for (const tool of mcpTools.filter((tool) => (tool.inputSchema.properties as any)?.offset)) {
+// Document tools also check portal profiles and join inbox receipts; covered in mcpDocuments.test.ts.
+for (const tool of mcpTools.filter((tool) => (tool.inputSchema.properties as any)?.offset && !tool.name.startsWith("documents."))) {
     test(`${tool.name}: retrieves 205 records across stable, bounded pages`, async () => {
         const db = drizzle(async (sql, params) => {
             if (sql.includes('from "tenants"')) return { rows: [["skr03"]] }