fix(billing): 页面文字溢出卡片 + 数字千分位

用户报 billing 页"文字超出展示框"。真因是三处叠加，都不是文案问题：

1. KPI 卡是 CSS grid，grid item 默认 min-width:auto。2e8 级的 prompt
   tokens（实测 270,149,209）无法收缩，于是把 grid 轨道撑出容器 → 整页横向
   溢出。修法是 min-width:0 + overflow:hidden（不给 min-width:0 的话，
   grid 子项永远不肯收缩，这是 grid 最常见的溢出坑）。
2. 表格写死 min-width:560px，窄视口下必然溢出。改 width:100% +
   table-layout:fixed，列宽由布局分配而不是由内容撑开。
3. 长名称（deepseek-v4.1-flash 这类模型 id）撑宽单元格。名称列改 ellipsis +
   title 悬停看全名；数字列 word-break:break-all 在列宽内换行。

顺手：所有 token/请求数走 toLocaleString 千分位。原始 9 位数字读起来要数
零位数，分组后 270,149,209 一眼可读，也顺带缩短了字符串宽度。

CDP 实测（820px 窄视口，逼出溢出条件）：
  main/body 横向溢出 = no
  table=338 < card=366（修复前 min-width:560 必然 > 366）
  KPI 输入 tokens = 270,149,209
  billing 页无控制台错误

残留（不影响布局）：表头 TH 在固定布局下 48>42 轻微超出自身格，因为
word-break 不拆单个长词；表格整体仍在容器内，未产生页面滚动。

全量测试全绿（8 包）。

internal/lua/plugins/billing.lua

@@ -547,21 +547,30 @@ plugin.ui = {
     if (!b.cache_reported_reqs) return "n/r";
     return ((hit / prompt) * 100).toFixed(1) + "%";
   }
+  // fmtInt 千分位分组：2e8 级 token 总数可读、也更短，降低撑宽风险。
+  function fmtInt(n) {
+    return (Number(n) || 0).toLocaleString("en-US");
+  }
   function row(name, b, cur) {
     var fresh = (b.cache_fresh_tokens === undefined) ? (b.prompt_tokens || 0) : b.cache_fresh_tokens;
-    return "<tr><td><b>" + esc(name) + "</b></td><td>" + money(b.cost, cur) +
+    // 名称列 ellipsis（title 悬停看全名）；数字列 break-all 在列宽内换行而不是
-      "</td><td>" + (b.requests || 0) + "</td><td>" + (b.prompt_tokens || 0) +
+    // 把表格撑出卡片。单元格结构与列数不变，列数判据不受影响。
-      "</td><td>" + fresh +
+    return "<tr><td style='overflow:hidden'><b style='display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis' title='" +
-      "</td><td>" + (b.cache_hit_tokens || 0) +
+      esc(String(name).replace(/'/g, "&#39;")) + "'>" + esc(name) + "</b></td>" +
-      "</td><td>" + esc(cacheRate(b)) +
+      "<td style='word-break:break-all'>" + money(b.cost, cur) + "</td>" +
-      "</td><td>" + (b.completion_tokens || 0) + "</td></tr>";
+      "<td style='word-break:break-all'>" + fmtInt(b.requests || 0) + "</td>" +
+      "<td style='word-break:break-all'>" + fmtInt(b.prompt_tokens || 0) + "</td>" +
+      "<td style='word-break:break-all'>" + fmtInt(fresh) + "</td>" +
+      "<td style='word-break:break-all'>" + fmtInt(b.cache_hit_tokens || 0) + "</td>" +
+      "<td style='word-break:break-all'>" + esc(cacheRate(b)) + "</td>" +
+      "<td style='word-break:break-all'>" + fmtInt(b.completion_tokens || 0) + "</td></tr>";
   }
   function tableFor(el, obj, cur, empty) {
     var keys = Object.keys(obj || {});
     if (!keys.length) { el.innerHTML = '<div class="muted">' + empty + "</div>"; return; }
     keys.sort(function (a, b) { return (obj[b].cost || 0) - (obj[a].cost || 0); });
     var TH = L();
-    var h = "<table style='width:100%;border-collapse:collapse;font-size:13px;min-width:560px'>" +
+    var h = "<table style='width:100%;border-collapse:collapse;font-size:13px;table-layout:fixed;word-break:break-word'>" +
       "<tr style='text-align:left;opacity:.65'><th>" + TH.thName + "</th><th>" + TH.thCost +
       "</th><th>" + TH.thReqs + "</th><th>" + TH.thPrompt +
       "</th><th>" + TH.thFresh + "</th><th>" + TH.thCache + "</th><th>" + TH.thCachePct +
@@ -589,20 +598,23 @@ plugin.ui = {
     var t = st.total || {};
     document.getElementById("billing-kpis").innerHTML = [
       [T.total, money(t.cost, cur)],
-      [T.requests, t.requests || 0],
+      [T.requests, fmtInt(t.requests || 0)],
-      [T.degraded, st.degraded_reqs || 0],
+      [T.degraded, fmtInt(st.degraded_reqs || 0)],
-      [T.unpriced, st.unpriced_reqs || 0],
+      [T.unpriced, fmtInt(st.unpriced_reqs || 0)],
-      [T.prompt, t.prompt_tokens || 0],
+      [T.prompt, fmtInt(t.prompt_tokens || 0)],
-      [T.completion, t.completion_tokens || 0],
+      [T.completion, fmtInt(t.completion_tokens || 0)],
       [T.failures, t.failures || 0],
       // Cache KPIs: last session added the table columns but the KPI cards
       // were left out — the edit's assert failed and the retry only re-did the
       // tables. The numbers existed in state and nowhere in the UI.
       [T.cacheRate, cacheRate(t)],
-      [T.cacheTokens, t.cache_hit_tokens || 0]
+      [T.cacheTokens, fmtInt(t.cache_hit_tokens || 0)]
     ].map(function (kv) {
-      return "<div class='card' style='padding:12px'><div style='font-size:11px;opacity:.65'>" +
+      // min-width:0：grid item 默认 min-width:auto，2e8 级长数字会把轨道撑出
-        kv[0] + "</div><div style='font-size:19px;font-weight:600;margin-top:4px'>" +
+      // 容器造成横向溢出。标签 nowrap 截断，数值 break-all 换行。
+      return "<div class='card' style='padding:12px;min-width:0;overflow:hidden'>" +
+        "<div style='font-size:11px;opacity:.65;white-space:nowrap;overflow:hidden;text-overflow:ellipsis'>" +
+        esc(kv[0]) + "</div><div style='font-size:19px;font-weight:600;margin-top:4px;word-break:break-all;line-height:1.2'>" +
         esc(kv[1]) + "</div></div>";
     }).join("");
     var TD = L();