STRICT ALLOWLIST policy: Only packages explicitly listed in CONVENTIONS.md
may be imported. No exceptions.
## Changes
- Updates CONVENTIONS.md with strict allowlist language
- Adds scripts/check-deps.sh to enforce the allowlist
- Adds 'make check-deps' and 'make precommit' targets
- CI will fail if any unapproved dependency is detected
## Approved packages
- gopkg.in/yaml.v3 — YAML parsing
- github.com/google/go-cmp — test comparisons
## Process for new dependencies
1. Open a PR that ONLY updates CONVENTIONS.md
2. Requires explicit approval from Aaron
3. After merge, a separate PR may use the package
Rodin