Migrate Files surfaces to interface patterns

docs/FILES_HANDBOOK.md

@@ -24,6 +24,10 @@ a document collaboration engine, or a records-management system.
 | Verify a release or scenario | [Acceptance scenarios](#acceptance-scenarios) |
 | Check whether an idea exists today | [Implemented and planned boundary](#implemented-and-planned-boundary) |
 
+The Files-owned interface archetypes, consequence classes, disabled-state
+wording, and verification evidence are recorded in
+[Files Interface Pattern Migration](INTERFACE_PATTERN_MIGRATION.md).
+
 ## The service contract
 
 A managed file is a tenant-scoped logical asset with exactly one user or group
@@ -185,6 +189,14 @@ inside the chosen owner space:
 
 Browse, import, and sync never write, rename, or delete the remote source.
 
+Connector administration separates endpoint profiles, reusable credentials,
+and inherited policy. Ordinary setup uses typed fields and provider discovery;
+provider metadata JSON is available only under advanced compatibility options.
+Read-only deployment entries explain where they must be changed, and disabled
+actions identify the missing permission, target, input, or running operation.
+The contextual help icon opens the configured Help Center topic when Docs is
+enabled and the hosted GovOPlaN documentation otherwise.
+
 ## Process perspective
 
 ### Managed ingestion