Update Base Platform Tools references for Base Foundry

[codeforester]

Context

base-platform-tools moved to basefoundry/base-platform-tools, but the README and migration notes still point at codeforester coordinates.

Scope

• Update clone instructions to https://github.com/basefoundry/base-platform-tools.git.
• Update docs and command READMEs that refer to migration from codeforester/base so they point at basefoundry/base where current rather than historical wording is intended.
• Update validation assertions in tests/validate.sh that currently require codeforester/base.
• Preserve genuinely historical changelog wording only if it is intentionally describing the pre-org move.

Validation

• rg -n "codeforester/base|github.com/codeforester" README.md docs cli tests CHANGELOG.md and review remaining hits as intentional.
• ./tests/validate.sh
• git diff --check