Add support for v2 evals that clone a real repo at a specific commit
instead of using bundled template source. The agent handles setup,
diagnosis, and fixing on its own.
- run-eval.sh: v1/v2 dispatch, repos/ directory, prompt from manifest
- First v2 eval: codeflash-internal psycopg serialization (PR #2489)
- EVAL-V2-SKETCH.md: design doc for the v2 eval system
- intro.md: repo onboarding guide