ci,scripts: install LLVM before cargo tools

[avi-starkware]

Reorder bootstrap and install_build_tools.sh so LLVM 19 is installed
before cargo tools. This is needed because install_cargo_tools.sh will
install starknet-native-compile which requires LLVM to build.

Safe change: LLVM installation does not depend on Rust.

---

Re-do of #13674, which was accidentally merged into avi/compiler-verify-fn
instead of main. The change itself (squash commit 08764c4529) is identical;
this PR cherry-picks that commit onto main.

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

[cursor]

PR Summary

Medium Risk
Moderate risk because it changes CI/bootstrap ordering and build-tool installation flow, which could break builds if dependencies.sh has implicit assumptions about the Rust toolchain or environment.

Overview
Ensures native build dependencies (via setup_native_deps / dependencies.sh, including LLVM) are installed before Rust/cargo tooling.

This reorders .github/actions/bootstrap to run native deps setup before install_rust, and updates scripts/install_build_tools.sh to execute ./dependencies.sh before install_cargo_tools.sh, adding explicit logging around the dependency step.

^{Reviewed by Cursor Bugbot for commit 23ee70d. Bugbot is set up for automated code reviews on this repo. Configure here.}

[reviewable-StarkWare]

This change is 

[github-actions]

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• Started at 2026-05-17T21:12:21Z

[dorimedini-starkware]

@dorimedini-starkware reviewed 2 files and all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on avi-starkware).