chore: unify code formatting and remove unused code

- Apply cargo fmt to Rust code with multiline error handling
- Apply Prettier formatting to TypeScript code with trailing commas
- Unify #[allow(non_snake_case)] attribute formatting
- Remove unused ProviderNotFound error variant from error.rs
- Add vitest-report.json to .gitignore to exclude test artifacts
- Optimize readability of error handling chains with vertical alignment

All tests passing: 22 Rust tests + 126 frontend tests

src/config/codexProviderPresets.ts

@@ -121,9 +121,7 @@ requires_openai_auth = true`,
       "https://www.dmxapi.cn/v1",
       "gpt-5-codex",
     ),
-    endpointCandidates: [
-      "https://www.dmxapi.cn/v1",
-    ],
+    endpointCandidates: ["https://www.dmxapi.cn/v1"],
   },
   {
     name: "PackyCode",