fix: read skill files as UTF-8 in validator

[BramVR]

- text = File.read(path)
+ text = File.read(path, encoding: "UTF-8")

Why

scripts/validate-skills read every SKILL.md with Ruby's default external encoding, which follows the process locale. In any shell without LANG set — including the non-interactive shells agents run in, and therefore the hooks/pre-commit gate — Ruby defaults to US-ASCII and every skill containing a non-ASCII byte fails YAML parsing with invalid byte sequence in US-ASCII.

Nineteen of the current skills trip it, since the house style uses em dashes and ≫ in descriptions. The failure looks like broken front matter but is purely environmental: the same files validate fine under LANG=en_US.UTF-8. Every commit in this repo today needed a LANG prefix to get past the hook.

Upstream steipete/agent-scripts fixed this; the same one-line fix was already sitting unmerged on the local claude/quirky-bartik-cdc137 branch. This cherry-picks that commit onto current main, preserving authorship, and adds a changelog entry.

Verification

Before, with the locale unset:

$ env -u LANG -u LC_ALL ./scripts/validate-skills
Skill validation failed:
- skills/oracle/SKILL.md: YAML: invalid byte sequence in US-ASCII
  ... 18 more
exit 1

After:

$ env -u LANG -u LC_ALL ruby -e 'puts Encoding.default_external'
US-ASCII
$ env -u LANG -u LC_ALL ./scripts/validate-skills
Validated 45 skill(s).
exit 0

Still US-ASCII as the process default — the fix is in the read, not the environment.

Note on the count: 45 here versus 47 in the main checkout. skills/gog and skills/wacrawl are relative symlinks (../../gogcli/...) that only resolve from the real checkout, so they dangle in a worktree and are skipped. Pre-existing behaviour, unrelated to this change.

[Copilot]

Pull request overview

Fixes locale-dependent failures in the skill validator by forcing UTF-8 when reading SKILL.md, ensuring the pre-commit hook and CI behave consistently even when LANG/LC_ALL are unset.

Changes:

• Read skill files with File.read(..., encoding: "UTF-8") in scripts/validate-skills.
• Add a changelog entry documenting the validator behavior change and the resolved error mode.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
scripts/validate-skills	Forces UTF-8 reads for SKILL.md to avoid US-ASCII default-external encoding failures when locale env vars are unset.
CHANGELOG.md	Documents the validator UTF-8 read fix and its impact on pre-commit/validation reliability.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.