Remove allowed-files restriction from evergreen workflow

[Copilot]

The evergreen agent's push-to-pull-request-branch was failing because the allowed-files list only permitted 5 .github/workflows/ files. Any PR fix touching source, tests, config, or playground files was rejected.

• Removed the allowed-files constraint from evergreen.md, matching how autoloop.md already handles this (no restriction = all files allowed)
• Recompiled evergreen.lock.yml via gh aw compile

Before:

safe-outputs:
  push-to-pull-request-branch:
    target: "*"
    max: 3
    allowed-files:
      - ".github/workflows/autoloop.lock.yml"
      - ".github/workflows/autoloop.md"
      - ".github/workflows/evergreen.lock.yml"
      - ".github/workflows/evergreen.md"
      - ".github/workflows/pages.yml"

After:

safe-outputs:
  push-to-pull-request-branch:
    target: "*"
    max: 3

Note: protected_files and protected_path_prefixes (e.g. .github/, lockfiles, CODEOWNERS) remain enforced by the compiler defaults — this only removes the allowlist filter.