feat(timeline): 结局金色浮层(重新观看 + 回到上一个选择)

播到结局时在镜头下方弹金色星标浮层：显示结局文案/成败/奖励 + 两个按钮——
「⟲ 重新观看」从头再播、「↶ 回到上一个选择」跳回最近分支点(位置重放正确)直接试另一条。
记录最近 choice/random/fight 节点供回跳；纯线性到结局则只显示重新观看。

web/static/style.css

@@ -283,6 +283,10 @@ body.perform-mode .mode-switch { border-color:#2f7a60; }
                  border:1px solid #8a7038; border-radius:6px; padding:8px 14px; font-size:13px;
                  cursor:pointer; box-shadow:0 2px 8px rgba(0,0,0,.55); }
 .tl-choice-btn:hover { background:#5a4a26; border-color:#e6c878; }
+/* 结局浮层：金色星标，区别于普通选项 */
+.tl-ending-q { color:#f2c463 !important; background:rgba(42,30,14,.9) !important; border:1px solid #8a6a30; font-size:13px; max-width:92%; }
+.tl-ending-btn { border-color:#b8893a; }
+.tl-ending-btn:hover { background:#5a4426; border-color:#f2c463; }
 /* 时间轴面板：固定/可拖高度、自己横向滚动 */
 .tl-timelinepanel { flex:none; height:200px; min-height:80px; display:flex; }
 .tl-tracks { position:relative; flex:1; min-width:0; overflow-x:auto; overflow-y:auto; cursor:grab;

web/static/timeline.js

@@ -219,7 +219,7 @@
   }
 
   // ===================== 状态 & 挂载 =====================
-  let S, model, playT = 0, playing = false, rafId = 0, lastTs = 0, stageCv, stageCtx, els = {}, pending = null, selNode = null, PX = 80, fitMode = false;
+  let S, model, playT = 0, playing = false, rafId = 0, lastTs = 0, stageCv, stageCtx, els = {}, pending = null, selNode = null, PX = 80, fitMode = false, lastDecisionId = null;
 
   const TEMPLATE =
     '<div class="tl-stagepanel">' +
@@ -309,7 +309,7 @@
   }
   // 从指定节点开始：先重放途中走位算进入位置，再从该节点构建演出。
   function startFrom(targetId, autoplay) {
-    stopPlay(); hideChoices(); clearSelection();
+    stopPlay(); hideChoices(); clearSelection(); lastDecisionId = null;
     const path = pathTo(S, targetId);
     S.entryPos = path ? replayPositions(S, path) : {};
     resetAccum(S);
@@ -436,6 +436,7 @@
 
   // ---- 选项浮层（镜头下方）----
   function showChoices(node, kind) {
+    lastDecisionId = node.id;   // 记录最近分支点，供结局「回到上一个选择」
     const box = els.choices; box.innerHTML = "";
     let q, opts;
     if (kind === "fight") {
@@ -483,8 +484,28 @@
     }
   }
   function onReachEnd() {
-    if (pending && (pending.kind === "choice" || pending.kind === "choice_once" || pending.kind === "fight" || pending.kind === "random"))
+    if (!pending) return;
+    if (pending.kind === "choice" || pending.kind === "choice_once" || pending.kind === "fight" || pending.kind === "random")
       showChoices(pending.node, pending.kind);
+    else if (pending.kind === "ending")
+      showEnding(pending.node);
+  }
+  function grantText(g) {
+    if (g.kind === "银两") return "银两" + (g.value > 0 ? "+" : "") + g.value;
+    if (g.kind === "道具") return "道具" + g.item + "×" + g.value;
+    if (g.kind === "友好度") return S.nm(g.target) + " 友好+" + g.value;
+    if (g.kind === "入门") return S.nm(g.target) + " 入门";
+    return g.kind;
+  }
+  function showEnding(node) {
+    const box = els.choices; box.innerHTML = "";
+    const res = { success: "成功", fail: "失败", end: "中性" }[node.result || "success"];
+    const grants = (node.grants && node.grants.length) ? "　奖励：" + node.grants.map(grantText).join("，") : "";
+    box.appendChild(Object.assign(document.createElement("div"), { className: "tl-choices-q tl-ending-q", textContent: "★ 结局：" + (node.summary || node.id) + "（" + res + "）" + grants }));
+    const mk = (txt, fn) => { const b = document.createElement("button"); b.className = "tl-choice-btn tl-ending-btn"; b.textContent = txt; b.onclick = fn; box.appendChild(b); };
+    mk("⟲ 重新观看", () => startFrom(firstNode(S.IR), true));
+    if (lastDecisionId && S.nodes[lastDecisionId]) mk("↶ 回到上一个选择", () => startFrom(lastDecisionId, true));
+    box.classList.remove("hidden");
   }
   function tick(ts) {
     if (!playing) return;