feedback5: merge W5E — a full hand refuses buys and reward picks, temp pieces fill freed slots (#82); 联防 plays on the official escaped maps (#41)

# Conflicts:
#	test/golden/fields.json
#	test/golden/matches.json

public/js/screens/game.js

@@ -362,11 +362,13 @@ function MatchScreen() {
   const shownMembers = shownField ? ((Array.isArray(pub?.fields) ? pub.fields : []).find((f) => f && f.fieldId === shownField.fieldId)?.players
     || (Array.isArray(shownField.players) ? shownField.players : null)) : null;
   const ownView = showPrep || (shownField ? (shownMembers ? shownMembers.includes(myId) : shownField.fieldId === ownFieldId(myId)) : !watchingOther);
+  // a field on a map of its own (联防: the escaped template's map, GitHub #41) shows that map; leaving it restores the board's
+  const fieldStage = gd.ready && shownField && shownField.stageId && shownField.stageId !== pub?.stageId ? gd.stage(shownField.stageId) : null;
   useEffect(() => {
     if (!view) return;
-    const st = ownView ? ownStage : baseStage;
+    const st = fieldStage || (ownView ? ownStage : baseStage);
     if (st) view.setStage(st);
-  }, [view, ownView, ownStage, baseStage]);
+  }, [view, ownView, ownStage, baseStage, fieldStage]);
   const staleFieldRef = useRef(null);
   const enteredFieldRef = useRef(null);
   const pressSel = useRef(null);                         // the selected piece when the current field press began

public/js/ui/gameLogic.js

@@ -731,15 +731,16 @@ export function mergeTarget(priv, chessId, getChess = () => null) {
   return { row: board[0].row, col: board[0].col, dir: board[0].dir || 'RIGHT' };
 }
 
-/** Whether every hand slot is taken (the server refuses a purchase / reward that needs a slot: HAND_FULL). */
+/** Whether every hand slot is taken (the server refuses every purchase / reward pick then: HAND_FULL, GitHub #82). */
 export function handFull(priv) {
   const hand = Array.isArray(priv?.hand) ? priv.hand : [];
   return hand.length >= GEO.HAND_SIZE && hand.every((p) => p != null);
 }
 
 /**
- * Would gaining one more `slot` (shop / reward card: { kind: 'chess'|'item', id }) complete a merge right away, so it
- * needs no hand slot? Mirror of server PlayerState completesChessMerge / completesItemMerge.
+ * Would gaining one more `slot` (shop / reward card: { kind: 'chess'|'item', id }) complete a merge right away? Mirror
+ * of server PlayerState completesChessMerge / completesItemMerge. (A full hand refuses such a purchase all the same:
+ * PRTS 卫戍协议/帮助 §手牌区, GitHub #82.)
  * @param {any} priv
  * @param {{kind?:string, id:string}} slot
  * @param {{ getChess?:(id:string)=>any, getItem?:(id:string)=>any, itemMergeCount?: number }} [o]
@@ -795,10 +796,10 @@ export function offerHeader(offer) {
 /**
  * Why a shop action is unavailable (null when available).
  * @param {'buy'|'reward'|'refresh'|'freeze'|'levelUp'|'ready'} kind
- * @param {{ priv:any, editable:boolean, slot?:any, getChess?:(id:string)=>any, getItem?:(id:string)=>any }} ctx
+ * @param {{ priv:any, editable:boolean, slot?:any }} ctx
  * @returns {string|null} Chinese reason
  */
-export function shopBlockReason(kind, { priv, editable, slot, getChess, getItem } = {}) {
+export function shopBlockReason(kind, { priv, editable, slot } = {}) {
   if (!priv) return '尚未就绪';
   if (priv.alive === false) return '你已被淘汰';
   if (kind === 'ready') return priv.canReady === false ? '临时整备区不为空，请先处理溢出的资源' : null;
@@ -811,7 +812,8 @@ export function shopBlockReason(kind, { priv, editable, slot, getChess, getItem
   if (kind === 'buy' || kind === 'reward') {
     if (!isObj(slot) || slot.sold) return kind === 'reward' ? '已选择' : '已售出';
     if ((Number(slot.price) || 0) > funds) return '资金不足';
-    if (handFull(priv) && !completesMerge(priv, slot, { getChess, getItem })) return '整备区已满';
+    // a full hand refuses every purchase / pick, a merge-completing one too (PRTS 卫戍协议/帮助 §手牌区, GitHub #82)
+    if (handFull(priv)) return '整备区已满';
     return null;
   }
   if (kind === 'refresh') return (Number(shop.refreshPrice) || 0) > funds ? '资金不足' : null;

public/js/ui/shopBar.js

@@ -37,7 +37,7 @@ function PriceHex({ slot, free, poor = false }) {
     title=${poor ? '资金不足' : tone === 'discount' ? `折扣价（原价 ${slot.basePrice}）` : tone === 'premium' ? `加价（原价 ${slot.basePrice}）` : '价格'} />`;
 }
 
-/** Data lookups for shopBlockReason (full-hand purchases that complete a merge stay allowed). */
+/** Data lookups (merge progress / target, the loadout; shopBlockReason ignores them — a full hand refuses every purchase). */
 const LOOKUPS = { getChess: (id) => data.lookup('chess', id), getItem: (id) => data.lookup('items', id) };
 
 /**