Update Codex profile config layout

[AarushiShah-db]

Summary

• Write ucode Codex settings to ~/.codex/ucode.config.toml for the new Codex profile loader.
• Remove ucode's legacy profile selector/table from shared ~/.codex/config.toml during configure.
• Require Codex CLI 0.134.0+ for the new profile-file layout, with a clear blocker for older installed versions.
• When ucode configure detects an older Codex CLI, warn that the update is required and run the Codex update path instead of treating it as optional.
• Update Codex unit tests and e2e harness paths for the profile-specific config file.

Tests

• uv run pytest --ignore=tests/test_e2e.py
• uv run pytest tests/test_agent_codex.py tests/test_agents_init.py
• uv run ty check src/
• uv run ruff check .
• uv run ruff format --check src/ tests/

Note

This intentionally requires updating older Codex CLIs instead of maintaining two config layouts. Codex CLI 0.134.0+ rejects legacy same-name profile config when launched with --profile, so
ucode now uses the profile-specific config file layout and blocks older Codex versions with: npm install -g @openai/codex or ucode configure.