[codex] Refactor API paths and admin i18n

[coding-hui]

Summary

• Refactor API routes and frontend clients to use versioned /api/v1 paths without /admin or /client segmentation.
• Extend exam snapshot/session/submission flows and judge repository behavior with focused tests.
• Improve admin i18n coverage, login language switching, placeholder routes, user role display, and desktop API proxy behavior.
• Update API/auth documentation for the new route shape.

Validation

• gofmt on changed Go files
• pnpm --dir apps/admin biome
• pnpm --dir apps/desktop biome
• GOCACHE=/tmp/examora-gocache go test ./...
• pnpm --dir apps/admin lint
• pnpm --dir apps/admin build
• pnpm --dir apps/desktop typecheck
• pnpm --dir apps/desktop build
• pnpm --dir website build
• git diff --check

Notes

• Local gh auth status reports the configured GITHUB_TOKEN is invalid, so PR creation used the GitHub connector after pushing the branch.

[chatgpt-codex-connector]

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