Document teams, gold sending, spectators and editor co-op runs

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

docs/MULTIPLAYER.md

@@ -76,8 +76,37 @@ per turn. Fog of war, particles and the camera are local and not part of the sha
   message); the relay keeps it in the room and adds it to the `start` message (room updates only show
   `"editor": true`). Every client builds the mission with `campaign::start_editor_coop_mission(doc, i, seed)` from
   the room's shared seed (rival masters of the map and the Rivals goal are left out, like in built-in co-op),
-  then the usual co-op setup. Block scripts run from side 0 in the fixed step. When the mission ends, the match
-  ends and the players go back to the lobby; there is no branching to a next mission and no progress is stored.
+  then the usual co-op setup. Block scripts run from side 0 in the fixed step.
+- **Editor campaign runs over several missions**: when a mission ends, the host's end dialog offers *Next mission*
+  (won: the branch of the reached goal, `CampaignDoc::next_mission_choice` with `Game::match_goal_done`) or *Try
+  again* (lost: the same mission); the others see "waiting for the host" and may leave. The host sends
+  `{"t":"next","mission":i,"seed":run_seed,"carry":[[side,Carry],..]}`; the relay checks that he is side 0 and that
+  the mission exists, resets the turn clock, drops pending orders and sends `next` (seed, sides, teams, AI seats,
+  carry, no campaign) to every client. The clients keep the campaign of the `start`, drop turns of the old mission
+  and build the new one with `start_editor_coop_mission(doc, i, run_seed)`, then `campaign::apply_coop_carry`.
+  The carry (`campaign::coop_carry_from`, computed by the host from the shared final world) is per master: his
+  five strongest creatures and 20% of his gold, like the single-player `Carry`. The host stores the progress
+  (missions done, chosen branches, run seed) in local storage under `dc.coop_editor_progress` (campaign name ->
+  `CampaignProgress`). A run ends when no next mission fits co-op.
+- **Teams in versus**: on the Match page every seat has a team A-D (default: a team of its own), set with
+  `{"t":"set_team","team":n}` for the own seat; the host may add `"side"` for a free or AI seat. Only before the
+  start. Room updates carry `team` per seat, the room list `teams`, and `start` a `teams` list in the order of
+  `sides` (`Game::set_teams`). Masters of one team are allies exactly like co-op partners (`Game::allied`: no
+  attacks, their creatures help each other, a tower spares them, the fog shows the team mates' ground, creatures
+  and towers). AI seats take part in teams as well.
+- **Fallen hearts**: a master whose soul core falls is out (`Game::out_sides`, shared state, in the checksum). His
+  creatures fight on without a heart (no economy: no mana, no new creatures, no payday), the creatures in his hand
+  are put down, the core tiles become floor and his orders are ignored. The player watches: no fog, free camera,
+  chat; the match goes on for the others (`Game::spectating`, local only).
+- **End of a match**: decided only from shared state (`Game::check_match_end`), so every client stops in the same
+  step: a versus match is over when only one team has masters (or AI seats) left - that team wins, the others lose;
+  if all seats are one team, the humans' gate is the enemy. A mission (co-op) is lost when every heart fell, and
+  won by its goals (mana springs count for any master). The checksum only mixes in *whether* the world still runs.
+- **Gold for allies**: `Act::SendGold { to, amount }` (100, 500, 1000 or all), in the creature overview and the
+  pause menu (the ally button switches between allies). It runs in the fixed step on every client, never sends
+  more than the sender has nor more than the receiver's treasury takes; the receiver gets a message and a sound.
+- **Room list**: rooms show what they play - versus, the built-in co-op mission, or the editor campaign's name and
+  the title of its current mission (`campaign`, `title` in `rooms` and `room`).
 - **Shared simulation side**: the shared part of a step (waves, units, towers, rivals, dwarves) runs with the
   first master switched in on every client; only the end check and the fog use the local master.
 
@@ -89,12 +118,12 @@ per turn. Fog of war, particles and the camera are local and not part of the sha
 | 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, 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 |
+| E | Alliances and co-op rules, AI masters for free and abandoned seats | built: co-op alliance, teams A-D in versus, sending gold, fallen hearts as spectators, AI seats |
 | 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: 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.
+| G | Editor campaigns in co-op over several missions (branches, carry, host progress), campaign names in the room list | built |
+
+Still open: own co-op campaign missions with story; how savegames treat a running match.
 
 ## Masters and sides