chore(evaluators): refresh contrib template packaging scaffold

[lan17]

Summary

• refresh the contrib template README so it documents the steady-state naming, install, and wiring contract
• rename the manifest placeholder from {{ORG}} to {{NAME}} and align package names, entry-point namespace, and version floors with the current contrib model
• add a template Makefile with the standard contrib target surface: test, lint, lint-fix, typecheck, check, and build

Why

The template was still describing an older contrib model and a misleading placeholder name. This change makes the scaffold match the current contract for real contrib packages while keeping template/ explicitly out of automation until it is converted into a real package.

Validation

• rendered the template into a scratch contrib package with placeholder substitution and parsed the resulting pyproject.toml
• ran make help in both the scratch package and evaluators/contrib/template
• ran make -n check in the scratch package to confirm the standard target surface resolves cleanly
• ran git diff --check on the changed template files

Design Context

• Shared design doc and implementation plan: https://gist.github.com/lan17/823617097f4b7e9f4ff717979de7dba4

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[lan17]

Superseded by #193, which rolls up this reviewed stack into one PR while preserving the logical commit boundaries for review.