feat(usage): turn refresh interval into a select and align control widths

Replace the click-to-cycle refresh button with a Select matching the
source/model filters. The "off" option now shows a localized label
(zh/en/ja/zh-TW) instead of the cryptic "--", and changing the interval
still invalidates all usage queries for an immediate refresh.

Align the top-bar controls into two width groups: source and model
selects at 120px, refresh select and date range trigger at 150px. The
date range button moves from auto width to fixed, so its long custom
range label gets truncate + hover title, and the calendar icon is
shrink-proofed.

src/i18n/locales/en.json

@@ -1446,6 +1446,8 @@
     "allModels": "All Models",
     "filterBySource": "Filter by source",
     "filterByModel": "Filter by model",
+    "refreshInterval": "Auto-refresh interval",
+    "refreshOff": "Off",
     "timeRange": "Time Range",
     "customRange": "Calendar Filter",
     "customRangeHint": "Supports both date and time",

src/i18n/locales/ja.json

@@ -1446,6 +1446,8 @@
     "allModels": "すべてのモデル",
     "filterBySource": "ソースで絞り込む",
     "filterByModel": "モデルで絞り込む",
+    "refreshInterval": "自動更新間隔",
+    "refreshOff": "オフ",
     "timeRange": "期間",
     "customRange": "カレンダーフィルター",
     "customRangeHint": "日付と時刻の両方に対応",

src/i18n/locales/zh-TW.json

@@ -1418,6 +1418,8 @@
     "allModels": "全部模型",
     "filterBySource": "依來源篩選",
     "filterByModel": "依模型篩選",
+    "refreshInterval": "自動重新整理間隔",
+    "refreshOff": "關閉",
     "timeRange": "時間範圍",
     "customRange": "日曆篩選",
     "customRangeHint": "支援日期與時間",

src/i18n/locales/zh.json

@@ -1446,6 +1446,8 @@
     "allModels": "全部模型",
     "filterBySource": "按来源筛选",
     "filterByModel": "按模型筛选",
+    "refreshInterval": "自动刷新间隔",
+    "refreshOff": "关闭",
     "timeRange": "时间范围",
     "customRange": "日历筛选",
     "customRangeHint": "支持日期与时间",