fix: expose Codex compact metadata in models

[icebear0828]

Summary

• include Codex token metadata in OpenAI-compatible model listings
• expose explicit auto compact token limits for CLI auto compaction
• cover the model metadata contract with a focused route test

Test plan

• git diff --check
• rg -n "as any|: any|" src/routes/models.ts tests/unit/routes/plan-routing-integration.test.ts src/models/model-store.ts src/types/openai.ts
• npx vitest run tests/unit/routes/plan-routing-integration.test.ts -t "includes Codex token metadata"
• npm run build