docs(plans): add combinatorial name suggestions milestone

docs/PROTOCOL.md

@@ -30,7 +30,6 @@ is only echoed for correlation; it grants no authority.
   Player names contain 1–32 UTF-8 bytes, have no control bytes or outer spaces,
   and are unique within the current lobby.
 - `restore`: `{"token":"32 lowercase hexadecimal characters"}`.
-- `suggest_name`: `{}`.
 - `start`: `{}`. Only connected Player 1 may use it, and both player slots must
   be connected.
 - `move`: `{"direction":"north|east|south|west"}`. Only a player in an active,
@@ -46,7 +45,6 @@ is only echoed for correlation; it grants no authority.
 
 - `session`: the private role result containing `role`, `slot`, and temporary
   `token`. The token is never included in a shared snapshot.
-- `name_suggestion`: an available humorous Russian player name.
 - `lobby`: the authoritative phase, revision, readiness, public player slots,
   connected observer count, and limits.
 - `countdown`: the single authoritative `[3,2,1]` event with common monotonic