Color-code avg response times on search page

- Green: <= 1500ms (fast, cheerio stores)
- Yellow: <= 4000ms (moderate, Puppeteer stores)
- Orange: > 4000ms (slow)
- Red: failing stores
- Grey: untested stores

Error durations are already excluded from the average (query
filters success = 1 only), so connection errors don't skew it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/src/routes/+page.svelte

@@ -183,7 +183,16 @@
                       : selectedStoreIds.has(store.id)
                         ? 'text-text-primary'
                         : 'text-text-tertiary'}">{store.name}</span>
-                  <span class="ml-auto text-2xs {isBroken ? 'text-red-400/50' : 'text-text-tertiary/40'}">
+                  <span class="ml-auto text-2xs
+                    {isBroken
+                      ? 'text-red-400/50'
+                      : store.last_scrape_ok === null
+                        ? 'text-text-tertiary/40'
+                        : store.avg_duration_ms <= 1500
+                          ? 'text-emerald-400/70'
+                          : store.avg_duration_ms <= 4000
+                            ? 'text-yellow-400/70'
+                            : 'text-orange-400/70'}">
                     {#if isBroken}
                       failing
                     {:else if store.last_scrape_ok === null}