Pin Colab Julia toolchain for Julia notebook bootstrap

[bernalde]

Summary

• pin the Colab-facing Julia verification path to 1.11.5, which matches the current Colab runtime
• fail fast in the notebook bootstrap when the running Julia version does not match the checked-in manifest, unless an explicit mismatch override is set
• support QUIP_REPO_REF in the Colab bootstrap so notebooks can clone the intended branch or commit instead of always defaulting to main
• refresh the Julia notebook manifest headers to Julia 1.11.5 and document the exact Colab toolchain expectations

Validation

• JULIA="$(JULIA_VERSION=1.11.5 ./scripts/find_julia.sh)" make verify-julia-colab-notebooks
• JULIA="$(JULIA_VERSION=1.11.5 ./scripts/find_julia.sh)" make verify-julia-colab-smokes

[Copilot]

Pull request overview

Updates the repo’s Julia notebook tooling and pinned Julia patch version to better match the current Colab runtime and enforce Manifest/kernel version consistency during Julia notebook bootstrap.

Changes:

• Pin default Julia version across local verification tooling to 1.11.5 (scripts/Makefile/docs).
• Add Julia Manifest parsing + runtime version validation to the Julia notebook bootstrap.
• Add an opt-in mechanism to checkout a specific QuIP git ref during Colab bootstrap via environment variable.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
scripts/verify_notebooks.py	Pins default Julia version used by local notebook execution/verification.
scripts/notebook_bootstrap.jl	Adds Manifest Julia version validation; adds optional git ref checkout for Colab bootstrap.
notebooks_jl/envs/1-MathProg/Manifest.toml	Updates julia_version metadata to 1.11.5.
notebooks_jl/envs/2-QUBO/Manifest.toml	Updates julia_version metadata to 1.11.5.
notebooks_jl/envs/3-GAMA/Manifest.toml	Updates julia_version metadata to 1.11.5.
notebooks_jl/envs/4-DWave/Manifest.toml	Updates julia_version metadata to 1.11.5.
notebooks_jl/envs/5-Benchmarking/Manifest.toml	Updates julia_version metadata to 1.11.5.
Makefile	Pins JULIA_VERSION default to 1.11.5 for notebook-related targets.
local-setup.md	Updates setup instructions to Julia 1.11.5 and documents new bootstrap env vars.

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