Fix irmin-client and irmin-server for Node type changes

- Add inline_contents_max_bytes to client Repo (returns 0)
- Simplify Node.merge type in client (key instead of key * key list)
- Simplify node_with_inlined type alias in server (key instead of
  key * key list)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: balat

src/irmin-client/client.ml

@@ -255,7 +255,7 @@ struct
               request t (module Merge) (old, a, b) |> Error.unwrap "Node.merge"
           | Error e -> Error e
         in
-        Irmin.Merge.v Irmin.Type.(option (pair Key.t (list Contents.Key.t))) f
+        Irmin.Merge.v Irmin.Type.(option Key.t) f
     end
 
     module Node_portable = Store.Backend.Node_portable
@@ -391,6 +391,7 @@ struct
 
       let v config = Lwt_eio.run_lwt @@ fun () -> connect config
       let config (t : t) = t.Client.config
+      let inline_contents_max_bytes _ = 0
       let close (t : t) = Lwt_eio.run_lwt @@ fun () -> Client.close t
       let contents_t (t : t) = t
       let node_t (t : t) = t

src/irmin-server/command.ml

@@ -211,7 +211,7 @@ struct
       let value_t = Node.Val.t
 
       type hash = Hash.t
-      type node_with_inlined = key * Contents.key list [@@deriving irmin]
+      type node_with_inlined = key [@@deriving irmin]
 
       module Mem = struct
         let name = "node.mem"

src/irmin-server/command_intf.ml

@@ -95,7 +95,7 @@ module type S = sig
       type key = Store.Backend.Node.key
       type value = Store.Backend.Node.value
       type hash = Store.Backend.Node.hash
-      type node_with_inlined = key * Store.Backend.Contents.key list
+      type node_with_inlined = key
 
       module Mem : CMD with type req = key and type res = bool
       module Find : CMD with type req = key and type res = value option