feat: v0.5.0 - provider icon actions, duplicate & connectivity test, dashboard chart fixes

- ProviderList: icon buttons (edit/copy/test/delete) via lucide-react, speed-test badge before enable/switch button
- Duplicate provider: deep-copy provider + models as xxx-copy
- test_connectivity command (cc-switch semantics: GET base_url, any HTTP response = reachable), latency badge green/orange/red, auto-dismiss 6s
- Dashboard: daily bars anchored to panel bottom, Card flex height fix (heatmap stays content-height)

src/i18n/en.ts

@@ -31,6 +31,13 @@ export const enTranslations: Record<TranslationKey, string> = {
   defaultModel: "Default: {name}",
   edit: "Edit",
   delete: "Delete",
+  copyProvider: "Duplicate provider",
+  testConnectivity: "Test connectivity",
+  testing: "Testing...",
+  connectivityOk: "{name} reachable ({latency}ms)",
+  connectivitySlow: "{name} reachable but slow ({latency}ms)",
+  connectivityFail: "{name} unreachable: {error}",
+  copiedProvider: "Duplicated as {name}",
 
   // Provider edit
   editProvider: "Edit Provider",