chore(evaluator): vendor code-evaluator + float-tol + scicode support

[jack-scitix-ai]

Type

• chore — CI, tooling, dependencies, config

Summary

• Convert code-evaluator from a git submodule (submodules/code-evaluator → scitix/code-evaluator) to a self-contained vendored copy under vendor/code-evaluator, byte-identical to the previously pinned commit e4802268. A plain git clone is now self-contained (no git submodule update). Requested in review.
• Port float-tol (fix/checker-messages-float-tol, cfc47d8): clearer LiveCodeBench output-comparison messages + opt-in float tolerance via CODE_EVAL_FLOAT_TOL (default off = exact ==, matching official LiveCodeBench).
• Add SciCode execution support: route source="scicode" through the direct-run path, add requirements/scicode.txt (numpy/scipy/sympy/matplotlib, pinned) and docker/Dockerfile.scicode (python:3.11-slim, since scipy 1.16.x needs Python ≥ 3.11). venv install remains supported.
• Retarget ruff/ty/mypy exclude from submodules/ to vendor/ so the vendored third-party code isn't linted/type-checked.
• Provenance recorded in vendor/code-evaluator/VENDORED.md; code-evaluator is an internal scitix repo with no separate LICENSE. No AI-generated Python modules in this PR (vendored third-party + config/docs only).
• The sieval-side SciCode dataset/task lands in a follow-up PR that depends on this one.

Test Plan

Automated

• Lint/format clean (ruff check && ruff format --check)
• Type check clean (ty check or mypy --strict)
• Unit tests pass (pdm run pytest)

Manual

• ty check sieval clean; ruff/format clean with vendor/ excluded; pdm run pytest tests/unit → 2379 passed. Vendored tree verified byte-identical to e4802268 (+ documented float-tol/scicode patches); app/*.py compile; source="scicode" alias present.

Checklist

Required (all PRs)

• PR title follows conventional format (type(scope): description)
• No internal paths, credentials, or personal info in committed files
• AI-generated code has AI-Generated Code - <model> (<provider>) in module docstring
• No new upper-layer dependencies added to core/
• Deleted code verified — no remaining call sites depend on it

[ethan-scitix]

Bug (blocking): Dockerfile:21 — COPY submodules /app/submodules is now dangling.
This PR removes submodules/ (gitlink + .gitmodules) but doesn't touch the Dockerfile. A fresh clone has no submodules/, so docker build fails on this line — defeating the PR's "self-contained clone" goal. It only builds locally because of an untracked leftover. The image bundles the eval service (L9 installs fastapi[standard]+psutil, which sieval itself doesn't use), so fix to COPY vendor /app/vendor (and update the launch path). Please pull the Dockerfile into this PR.

---

Question: float-tol paths disagree on "integer expected value" (vendor/code-evaluator/app/exec_py_test.py). _decimals_match (stdio) is value-based (b.to_integral_value() → 1.0 treated as integer, exact), while _value_close (fn-call, L54) is type-based (isinstance(b, int) → float 1.0 gets tolerance). Same logical 1.0 compares exact in one path, tolerant in the other. Opt-in only (default off) and byte-identical to upstream cfc47d8, so not blocking — worth aligning upstream or noting in _value_close's docstring that it keys off type.

---

Nit: VENDORED.md is bloated + partly wrong — slim it to provenance or drop it. Keep only what git can't: upstream URL + pinned SHA + patch list with source commits. Current issues: "internal scitix repo" is wrong (scitix/code-evaluator is public); the modifications list omits README.md (also patched); the service description and scipy/Python-3.11 note duplicate the vendored README and the requirements/scicode.txt + Dockerfile.scicode comments.