Show SPA e621 request times in the status pill

- New e621 metrics store tracks request count, cumulative time and the
  last request (path + duration) for the session
- The e621 client measures each request around fetch and JSON parsing
- Status pill appends a teal 'e621: <total>' segment with a tooltip
  showing request count and the last request; a server-side e621 time
  is shown separately if the backend ever reports one

frontend/src/components/StatusPill.tsx

@@ -2,6 +2,7 @@ import { Laptop, Monitor, Terminal, type LucideIcon } from "lucide-react";
 
 import { cn } from "@/lib/cn";
 import type { SystemStatus } from "@/lib/types";
+import { useE621Metrics } from "@/store/e621Metrics";
 
 const osIcons: Record<string, LucideIcon> = {
   linux: Terminal,
@@ -10,10 +11,16 @@ const osIcons: Record<string, LucideIcon> = {
 };
 
 function formatMs(value: number): string {
-  return value >= 100 ? `${Math.round(value)}ms` : `${value.toFixed(1)}ms`;
+  if (value >= 1000) return `${(value / 1000).toFixed(1)}s`;
+  if (value >= 100) return `${Math.round(value)}ms`;
+  return `${value.toFixed(1)}ms`;
 }
 
 export function StatusPill({ status }: { status?: SystemStatus }) {
+  const requestCount = useE621Metrics((state) => state.requestCount);
+  const totalMs = useE621Metrics((state) => state.totalMs);
+  const last = useE621Metrics((state) => state.last);
+
   if (!status) return null;
   const OsIcon = osIcons[status.os.icon] ?? Monitor;
 
@@ -37,10 +44,25 @@ export function StatusPill({ status }: { status?: SystemStatus }) {
       <span>{status.os.name}</span>
       <span className="text-ctp-surface2">·</span>
       <span>{formatMs(status.server_time_ms)}</span>
+      {requestCount > 0 ? (
+        <>
+          <span className="text-ctp-surface2">·</span>
+          <span
+            className="text-ctp-teal"
+            title={`${requestCount} e621 request${
+              requestCount === 1 ? "" : "s"
+            } this session · last ${last ? `${formatMs(last.ms)} (${last.path})` : "—"}`}
+          >
+            e621: {formatMs(totalMs)}
+          </span>
+        </>
+      ) : null}
       {status.e621_time_ms !== null ? (
         <>
           <span className="text-ctp-surface2">·</span>
-          <span>e621: {formatMs(status.e621_time_ms)}</span>
+          <span title="Server-side e621 time">
+            e621 (server): {formatMs(status.e621_time_ms)}
+          </span>
         </>
       ) : null}
     </span>

frontend/src/lib/e621.ts

@@ -1,10 +1,11 @@
+import { useE621Metrics } from "@/store/e621Metrics";
+
 export interface E621Credentials {
   username: string;
   api_key: string;
   base_url: string;
   configured: boolean;
 }
-
 export interface E621User {
   id: number;
   name: string;
@@ -141,26 +142,33 @@ export function e621Request<T>(
       );
     }
 
-    const response = await fetch(url, {
-      method: options.method ?? "GET",
-      headers,
-      body: options.body,
-      signal: options.signal,
-    });
+    const startedAt = performance.now();
+    try {
+      const response = await fetch(url, {
+        method: options.method ?? "GET",
+        headers,
+        body: options.body,
+        signal: options.signal,
+      });
 
-    if (!response.ok) {
-      let data: unknown = null;
-      try {
-        data = await response.json();
-      } catch {
-        data = null;
+      if (!response.ok) {
+        let data: unknown = null;
+        try {
+          data = await response.json();
+        } catch {
+          data = null;
+        }
+        throw new E621Error(response.status, data);
       }
-      throw new E621Error(response.status, data);
+      if (response.status === 204) {
+        return undefined as T;
+      }
+      return (await response.json()) as T;
+    } finally {
+      useE621Metrics
+        .getState()
+        .record(path, performance.now() - startedAt);
     }
-    if (response.status === 204) {
-      return undefined as T;
-    }
-    return (await response.json()) as T;
   });
 }
 

frontend/src/store/e621Metrics.ts

@@ -0,0 +1,31 @@
+import { create } from "zustand";
+
+export interface E621RequestSample {
+  path: string;
+  ms: number;
+  at: number;
+}
+
+interface E621MetricsState {
+  requestCount: number;
+  totalMs: number;
+  last: E621RequestSample | null;
+  record: (path: string, ms: number) => void;
+  reset: () => void;
+}
+
+/** Rolling e621 request timings for the current SPA session. */
+export const useE621Metrics = create<E621MetricsState>((set) => ({
+  requestCount: 0,
+  totalMs: 0,
+  last: null,
+
+  record: (path, ms) =>
+    set((state) => ({
+      requestCount: state.requestCount + 1,
+      totalMs: state.totalMs + ms,
+      last: { path, ms, at: Date.now() },
+    })),
+
+  reset: () => set({ requestCount: 0, totalMs: 0, last: null }),
+}));