fix(usage): align table width and reduce default window size

- stretch the usage table to match card width
- set the default window size to 1280 × 800
- migrate the legacy default window dimensions
- add coverage for window size migration

src/pages/UsageRecordsPage.tsx

@@ -1556,7 +1556,10 @@ function EventsView({
 
       {events.items.length ? (
         <div ref={tableWrapRef} className="usage-table-wrap">
-          <table className="usage-events-table" style={{ width: `${totalTableWidth}px` }}>
+          <table
+            className="usage-events-table"
+            style={{ width: `max(100%, ${totalTableWidth}px)` }}
+          >
             <colgroup>
               {visibleColumns.map((col) => (
                 <col key={col.key} style={{ width: `${widths[col.key]}px` }} />

src/styles.css

@@ -6617,8 +6617,12 @@ textarea:focus-visible {
 
 .usage-records-page {
   display: grid;
+  width: 100%;
+  max-width: 100%;
+  min-width: 0;
   gap: 12px;
   align-content: start;
+  justify-items: stretch;
 }
 
 .usage-topbar {
@@ -7199,6 +7203,8 @@ textarea:focus-visible {
 /* Events Tab (请求明细) */
 .usage-events-panel {
   display: flex;
+  width: 100%;
+  max-width: 100%;
   min-height: 0;
   padding: 0;
   flex-direction: column;