[tooling] scripts/anvil_fork.sh not committed with execute bit — fresh clone breaks quickstart

[obchain]

Refs #52

File: scripts/anvil_fork.sh

Problem

Git does track file mode if set before commit. If added with git add without prior chmod +x, it lands as 0644. README quickstart likely says ./scripts/anvil_fork.sh which fails with permission denied on fresh clone.

Fix

chmod +x scripts/anvil_fork.sh
git add --chmod=+x scripts/anvil_fork.sh

Verify with git ls-files -s scripts/anvil_fork.sh — mode field should be 100755.

[obchain]

Already satisfied on feat/24-anvil-fork (ffae806): git ls-files -s scripts/anvil_fork.sh reports mode 100755 (executable bit committed).