Translate campaign editor and scripting docs, update status

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/MULTIPLAYER.md

@@ -53,19 +53,37 @@ per turn. Fog of war, particles and the camera are local and not part of the sha
 - Savegames, tests and the standalone file are unchanged: `cargo test --release` covers the command path
   (including "the same actions on both paths build the same world").
 
+## Server and client
+
+- **Relay** (`server/src/netplay.rs`, route `/api/netplay/ws`, proxied by nginx): rooms with a six-letter code,
+  seats, ready flags, a 100 ms turn clock, checksum forwarding, chat (`all` / `team` channel), pause when a player
+  is missing (`resume` by side 0), `abort`, `leave` (a started human seat becomes AI-controlled), `set_ai` for
+  empty seats before the start, and a `ping`/`pong` round trip. The message list is at the top of the file.
+- **Client bridge** (`src/lobby.rs`, WebSocket in `www/dc_plugin.js`): `MatchClient` turns orders into JSON and
+  turns back into commands, tracks the lobby state (rooms, seats, AI seats), chat and the relay ping (`ping_ms`,
+  shown by the ping debug overlay).
+- **Menu**: *Multiplayer* in the title menu with the match list, create (versus or co-op mission), join by code,
+  seat choice, AI seat toggles for the host, ready/start, chat; the match keeps running in the background while
+  menus are open.
+- **AI seats** (`Game::sync_ai_sides`): empty seats marked by the host and seats of players who left are played
+  by the simplified rival AI on every client, so they stay deterministic.
+- **Co-op** (`Game::coop`): the master sides are allies against the heroes; allied creatures never target each
+  other, allied ground does not block claims. Co-op campaign matches use `campaign::start_coop_mission`.
+
 ## Steps
 
 | # | Step | Status |
 |---|---|---|
 | A | Simulation per master: gold, mana, research, rooms, hand, flag, traps, payday... per side; up to four masters (red, green, blue, yellow) | built |
 | B | All player actions as commands (`Command` + `Game::apply`), single player uses the same path; fixed time step | built |
-| C | Server: lobby and match relay over WebSocket (axum), turns, pause on disconnect, AI takeover on leave, chat | next |
-| D | Client: *Multiplayer* menu (lobby, create, join, ready, teams), WebSocket bridge in `dc_plugin.js`, chat, gold sending | planned |
-| E | Alliances and coop rules, AI masters for free and abandoned slots | planned |
-| F | Coop campaign: 20 missions with story (EN/DE) | planned |
+| C | Server: lobby and match relay over WebSocket (axum), turns, pause on disconnect, AI takeover on leave, chat, ping | built |
+| D | Client: *Multiplayer* menu (lobby, create, join, seats, ready), WebSocket bridge in `dc_plugin.js`, chat, ping | built |
+| E | Alliances and co-op rules, AI masters for free and abandoned seats | partly built: co-op alliance and AI seats work; free teams in versus and sending gold are missing |
+| F | Co-op campaign: 20 missions with story (EN/DE) | partly built: co-op matches reuse the single player missions that fit the master areas (`coop_mission_indexes`); no own co-op missions or story yet |
 
-Still open on the way to C: heroes and alliances for the new sides (today the hero gate path always leads to
-side 0's core, and in free play 2 and 3 are the rivals' sides), and what a match leaves out of savegames.
+Still open: teams/alliances in versus, sending gold to allies, own co-op campaign missions with story; still to be
+checked against the decisions above: a fallen heart only knocking out that player (who may keep watching), and how
+savegames treat a running match.
 
 ## Masters and sides