fix(usage): tighten request log column spacing

The request log has more columns than the other usage tables, so at the
default window size the last column (first token) was cut off and the
table had to scroll sideways. Its columns are already sized to their
content, so the model column had no slack to give back.

Narrow the gaps for this table only: 16px between columns (was 24px) and
32px between column groups (was 40px), keeping the 16px outer edges. The
table shrinks by 72px with the same rows; model names are not truncated.
The provider, model and pricing tables keep their spacing.

src/components/usage/RequestLogTable.tsx

@@ -619,7 +619,8 @@ export function RequestLogTable({
             key: id,
             className: cn(
               cells[id].props.className,
-              groupBreaks.has(id) && usageTable.groupGap,
+              usageTable.denseCell,
+              groupBreaks.has(id) && usageTable.denseGroupGap,
               pin.className,
             ),
             style: pin.style,
@@ -671,7 +672,8 @@ export function RequestLogTable({
                     ref={index === 0 ? firstHeadRef : undefined}
                     className={cn(
                       usageTable.th,
-                      groupBreaks.has(id) && usageTable.groupGap,
+                      usageTable.denseCell,
+                      groupBreaks.has(id) && usageTable.denseGroupGap,
                       pin.className,
                     )}
                     style={pin.style}

src/components/usage/usageTable.ts

@@ -23,6 +23,9 @@ export const usageTable = {
   td: "whitespace-nowrap px-3 first:ps-4 last:pe-4",
   /** 列组之间多留的间距（请求日志按身份 / 成本 / Tokens / 性能分组）：组内列距 24px，换组处 40px */
   groupGap: "ps-7",
+  /** 请求日志列多，收紧一档：组内列距 16px，换组处 32px（叠在 th / td / groupGap 之后，首尾 16px 不变） */
+  denseCell: "px-2 first:ps-4 last:pe-4",
+  denseGroupGap: "ps-6",
   mono: "font-mono text-caption",
   muted: "text-fg-3",
   empty: "py-10 text-center text-body text-fg-3",