chore: Dependency doc

[wisniewskij]

Summary

Adds reanimated-doctor (yarn doctor) — a check that the host tools this repo depends on but does not install via yarn install match the versions the repo expects.

Motivation. Tools like clang-format, clang-tidy, cmake, cmake-format/cmake-lint, ruby, cocoapods, the JDK and the NDK are not version-enforced on a contributor's machine, so a local version can silently differ from CI's. The usual symptom is a "works on my machine" formatting/lint diff that fails CI for no obvious reason. This consolidates the existing scattered guards (disallow-non-exact.js, check-ruby-pods.sh, .nvmrc) into one place.

Approach — derive, don't duplicate. Every required version is read at runtime from the file that already pins it, so there's no second copy to drift:

Tool	Source of the required version
node	.nvmrc
yarn	package.json#packageManager
clang-format	node_modules/.bin/clang-format (the clang-format-node pin) vs the binary on PATH
ruby	apps/fabric-example/Gemfile.lock (RUBY VERSION)
cocoapods	Podfile.lock COCOAPODS:, probed via bundle exec pod
cmake-format / cmake-lint	.github/actions/android-validation/action.yml (cmakelang==)
java (JDK)	CI java-version in android-validation
cmake	cmake_minimum_required() floor in CMakeLists.txt
NDK	apps/fabric-example/android/build.gradle (ndkVersion)
clang-tidy / clangd / xcode-build-server	genuinely unpinned — reported as info, not asserted

Cross-file consistency. It also flags repo files that disagree with each other. Currently surfaces four real inconsistencies: Gradle wrapper 9.3.1 vs 9.0.0, Spotless 8.4.0 vs 8.1.0, CI Java 17 vs 18, and Ruby 3.3.7 (.ruby-version) vs 3.3.6p108 (Gemfile.lock + CI guard).

Behaviour. Advisory by default — exits 0 and prints only rows that need attention. --display-all also shows passing rows; --ci makes error-severity findings (node/yarn) exit non-zero. No new dependencies, no build step. macOS-only checks (ruby/cocoapods/xcode-build-server) are skipped on Linux. Not yet wired into git hooks or CI — intentionally advisory first.

Note: this script is mostly AI-generated (disclosed in the file header).

Test plan

# default: only rows needing attention + cross-file conflicts; exits 0
yarn doctor

# show passing rows too
node scripts/doctor/doctor.js --display-all

# enforce: non-zero exit if node/yarn (error-severity) mismatch the repo pins
node scripts/doctor/doctor.js --ci ; echo "exit: $?"