Update Base Foundry references

[codeforester]

Summary

• Update README Homebrew, release, clone, and Base links to Base Foundry coordinates.
• Update lib/bash README to point at the Base Foundry Base source repo.
• Add validation coverage for stale codeforester README coordinates.

Validation

• rg -n "codeforester/base|github.com/codeforester" README.md lib/bash/README.md
• ./tests/validate.sh
• git diff --check

Fixes #38