feat: Add compiler_unstable_features to Nargo.toml

[aakoshh]

Description

Problem*

Resolves #9164

Summary*

Adds a new compiler_unstable_features field to Nargo.toml under [package], which can be used by the current package or its dependencies to require an unstable feature to be enabled during compilation for files in that crate.

This allows the LSP to pick up whether the currently edited package does or doesn't need a feature, without having to edit the plugin settings where CLI arguments can be passed.

The requirement is on a crate-by-crate basis, so if dependency foo requires enums, but another dependency bar does not state that it does, then it would be an error in bar to use a match, unless the feature is enabled globally via CLI with -Zenums.

Required unstable features are ignored if features are explicitly enabled on the CLI, e.g. if foo requires enums, but we pass -Zownership, then enums are still disabled, because we interpret -Z as the developer taking control of what exactly is acceptable globally.

The PR also adds a --no-unstable-features CLI argument to ignore all requirements in manifests, in case someone finds it important to make sure no unstable features sneaked in from dependencies.

Additional Context

Example:

[package]
name = "fuzz_testing"
type = "bin"
authors = [""]
compiler_unstable_features = ["enums"]

[dependencies]

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Execution Time'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 9e6e073	Previous: 39a504c	Ratio
rollup-root	0.005 s	0.004 s	1.25

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Compilation Time'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 32dd1a6	Previous: e5c6d5d	Ratio
rollup-block-root-single-tx	255 s	196 s	1.30

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[github-actions]

🚀 Deployed on https://6878ea148061f046050896da--noir-docs.netlify.app

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Test Suite Duration'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 2ddd080	Previous: 69827d1	Ratio
test_report_zkpassport_noir_rsa_	2 s	1 s	2

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[github-actions]

FYI @noir-lang/developerrelations on Noir doc changes.