0.2.3: Clementia S2 releases a dead, hidden, uncarriable or pathless rider at once (slot and weight back before the same tick's boarding checks); same-browser match recovery never takes the seat of a window that is reloading or still starting (a tab keeps its own session token; seats are stamped at the server's welcome, the older welcome wins); golden: diy-135 moves (outcome unchanged)

shared/protocol.js

@@ -378,7 +378,8 @@ const target = (v) => {
 /** @type {Record<string, Record<string, (v:any)=>boolean> & { $optional?: string[] }>} */
 export const C2S = {
   // session & lobby
-  hello: { name: (v) => isStr(v, NAME_MAX_LEN) && v.trim().length > 0, token: (v) => v == null || isStr(v, 64), version: (v) => v == null || isInt(v, 0, 1e6), $optional: ['token', 'version'] },
+  hello: { name: (v) => isStr(v, NAME_MAX_LEN) && v.trim().length > 0, token: (v) => v == null || isStr(v, 64), version: (v) => v == null || isInt(v, 0, 1e6),
+    noReplace: isBool, claimAt: (v) => isNum(v, 0, Number.MAX_SAFE_INTEGER), $optional: ['token', 'version', 'noReplace', 'claimAt'] },
   ping: { c: (v) => typeof v === 'number' && Number.isFinite(v) },
   'room.create': { mode: (v) => v === 'solo' || v === 'coop', difficulty: (v) => DIFFICULTIES.includes(v) },
   'room.join': { code: (v) => isStr(v, ROOM_CODE_LEN + 2) && /^[A-Za-z0-9]+$/.test(v) },