fix(gh-test-evidence): update imports to use new lib/github path

Update imports to match the refactored GitHub client location:
- @/src/gh → @/lib/github
- @/src/ghc → @/lib/github/githubCached

Fixes CI error: Cannot find module '@/src/gh'

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: snomiao

app/tasks/gh-test-evidence/gh-test-evidence.ts

@@ -1,6 +1,6 @@
 import { db } from "@/src/db";
-import { gh } from "@/src/gh";
-import { ghc } from "@/src/ghc";
+import { gh } from "@/lib/github";
+import { ghc } from "@/lib/github/githubCached";
 import { ghUser } from "@/src/ghUser";
 import { parseIssueUrl } from "@/src/parseIssueUrl";
 import { parseGithubRepoUrl } from "@/src/parseOwnerRepo";