chore: general maintenance and cleanup (#306)

.claude/skills/yaml-validate/SKILL.md

@@ -0,0 +1,38 @@
+---
+name: yaml-validate
+description: >-
+  Validate YAML files after editing.
+  Apply when writing or modifying any .yml or .yaml file.
+user-invocable: false
+allowed-tools: Bash, Read
+---
+
+After editing any YAML file, validate it:
+
+## 1. Syntax check
+
+Run yamllint on the file:
+
+```bash
+yamllint <file>
+```
+
+If yamllint is not available, fall back to:
+
+```bash
+python3 -c "import yaml; yaml.safe_load(open('<file>'))"
+```
+
+## 2. GitHub Actions workflows
+
+If the file is under `.github/workflows/`, also run:
+
+```bash
+actionlint <file>
+```
+
+If actionlint is not available, skip silently.
+
+## Files to skip
+
+- `config/gh/hosts.yml` — managed by `gh` CLI, not hand-edited