feat(hub-client): GetInstalledModuleDocs + per-file MIME

- New getInstalledModuleDocs(name, locale) wraps the new gRPC
  RPC; callers get text + source path + a not-installed flag so
  Studio can decide whether to show a Documentation section at
  all.
- runSavedFlow gains an optional fileMimeTypes map keyed
  parallel to fileInputs. Hard-coded application/octet-stream
  remains as the fallback, but text.extract and other
  MIME-gating modules now get an accurate type when the caller
  knows one.
- fetchModuleDocs is marked @Deprecated; it still works for
  older consumers but Studio no longer calls it.
- Proto bindings regenerated against fai/platform proto.

Signed-off-by: flemming-it <sf@flemming.it>
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/src/hub_client.dart

@@ -59,6 +59,7 @@ typedef ClearEventLogResponse = pb.ClearEventLogResponse;
 typedef DaemonPathsResponse = pb.DaemonPathsResponse;
 typedef UninstallModuleResponse = pb.UninstallModuleResponse;
 typedef FetchModuleDocsResponse = pb.FetchModuleDocsResponse;
+typedef GetInstalledModuleDocsResponse = pb.GetInstalledModuleDocsResponse;
 typedef ListMcpClientsResponse = pb.ListMcpClientsResponse;
 typedef McpClientStatus = pb.McpClientStatus;
 typedef McpClientConfigEntry = pb.McpClientConfigEntry;
@@ -240,6 +241,10 @@ class HubClient {
   /// when set, so Studio doesn't have to handle credentials.
   /// Errors come back inside [FetchModuleDocsResponse.errorKind]
   /// (not as exceptions) so the UI can render fallbacks.
+  ///
+  /// Deprecated: prefer [getInstalledModuleDocs], which reads
+  /// `MODULE.md`/`MODULE.<locale>.md` shipped inside the bundle.
+  @Deprecated('Use getInstalledModuleDocs (reads from bundle, no network)')
   Future<FetchModuleDocsResponse> fetchModuleDocs(
     String name, {
     String locale = '',
@@ -249,6 +254,25 @@ class HubClient {
     );
   }
 
+  /// Read the installed module's `MODULE.md` (or `MODULE.<locale>.md`)
+  /// from disk under `~/.fai/modules/<module>/`. No network. Works in
+  /// air-gapped installs. The response distinguishes three states via
+  /// [GetInstalledModuleDocsResponse.notInstalled] and an empty
+  /// [GetInstalledModuleDocsResponse.text]:
+  ///
+  /// - text non-empty → docs found, render them
+  /// - text empty + notInstalled=false → installed but bundle had
+  ///   no inline docs
+  /// - text empty + notInstalled=true → module is not installed
+  Future<GetInstalledModuleDocsResponse> getInstalledModuleDocs(
+    String name, {
+    String locale = '',
+  }) {
+    return _admin.getInstalledModuleDocs(
+      pb.GetInstalledModuleDocsRequest(name: name, locale: locale),
+    );
+  }
+
   /// List every configured MCP server with the last-discovery
   /// snapshot. Drives Studio's MCP-clients editor.
   Future<ListMcpClientsResponse> listMcpClients() {
@@ -489,27 +513,33 @@ class HubClient {
   /// flow that mixes text and binary inputs (e.g. extract
   /// taking a `document: bytes`) flows through one RPC:
   ///   * [textInputs] — string values wrapped as text Payloads
-  ///   * [fileInputs] — raw bytes wrapped as bytes Payloads,
-  ///                     with `application/octet-stream` MIME
-  ///                     type. Caller can override the MIME by
-  ///                     passing a [bytePayloads] entry instead.
-  /// Both maps default to empty so existing text-only callers
+  ///   * [fileInputs] — raw bytes wrapped as bytes Payloads.
+  ///                     MIME type defaults to
+  ///                     `application/octet-stream`; clients that
+  ///                     know the real type pass it via
+  ///                     [fileMimeTypes] (same key). Modules
+  ///                     typically gate on MIME — e.g.
+  ///                     `text.extract` rejects octet-stream — so
+  ///                     accurate types matter.
+  /// All maps default to empty so existing text-only callers
   /// are backward-compatible. Keys must not collide between
-  /// the maps; on collision the bytes-shaped entry wins (the
-  /// less-common case is more likely to be the operator's
-  /// intent).
+  /// [textInputs] and [fileInputs]; on collision the bytes-shaped
+  /// entry wins (the less-common case is more likely to be the
+  /// operator's intent).
   Future<SubmitResponse> runSavedFlow({
     required String name,
     Map<String, String> textInputs = const {},
     Map<String, Uint8List> fileInputs = const {},
+    Map<String, String> fileMimeTypes = const {},
   }) async {
     final req = pb.RunSavedFlowRequest()..name = name;
     for (final entry in textInputs.entries) {
       req.inputs[entry.key] = pb_common.Payload()..text = entry.value;
     }
     for (final entry in fileInputs.entries) {
+      final mime = fileMimeTypes[entry.key] ?? 'application/octet-stream';
       final bytes = pb_common.Bytes()
-        ..mimeType = 'application/octet-stream'
+        ..mimeType = mime
         ..data = entry.value;
       req.inputs[entry.key] = pb_common.Payload()..bytes = bytes;
     }