Align lint fixes with main and resolve merge conflicts

- Convert biome-ignore to oxlint-disable-next-line across client app
- Fix no-base-to-string with type narrowing instead of suppressions
- Fix no-floating-promises with fireAndForget() in proxy app
- Fix restrict-template-expressions with String() wrapping
- Resolve leftover merge conflict markers in manager.rs
- Remove duplicate cmd_plugin_init_errors from lib.rs
- Add graphql as explicit dependency in yaak-client

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/yaak-client/components/Settings/SettingsCertificates.tsx

@@ -236,7 +236,7 @@ export function SettingsCertificates() {
         <VStack space={3}>
           {certificates.map((cert, index) => (
             <CertificateEditor
-              // biome-ignore lint/suspicious/noArrayIndexKey: Index is fine here
+              // oxlint-disable-next-line react/no-array-index-key
               key={index}
               certificate={cert}
               index={index}