[Security] Gate per-request multimodal processor kwargs (#58830)

Signed-off-by: Juan Pérez de Algaba <jperezde@redhat.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

rust/src/cmd/src/cli/unsupported.rs

@@ -409,6 +409,17 @@ pub struct ServerUnsupportedArgs {
     )]
     pub trust_request_chat_template: Option<Unsupported>,
 
+    /// Whether to trust per-request multimodal kwargs (`mm_processor_kwargs`
+    /// and `media_io_kwargs`). If False, the server rejects non-empty values
+    /// because they can change multimodal preprocessing resource usage.
+    #[arg(
+        long,
+        visible_alias = "no-trust-request-mm-kwargs",
+        default_missing_value = "true",
+        num_args = 0..=1
+    )]
+    pub trust_request_mm_kwargs: Option<Unsupported>,
+
     /// The role name to return if `request.add_generation_prompt=true`.
     #[arg(long)]
     pub response_role: Option<Unsupported>,