fix(cargo): skip binstall for cargo install options

[risu729]

Summary

• fall back to cargo install when cargo tool options require source-build feature selection
• keep cargo-binstall for compatible options such as bin, crate, and locked
• document that cargo-binstall owns its own artifact/compile fallback; mise does not retry cargo install after a cargo-binstall failure
• document cargo-binstall behavior for cargo settings and tool options

Testing

• cargo fmt --all --check
• git diff --check
• MISE_TRUSTED_CONFIG_PATHS=$PWD mise x prettier -- prettier --check docs/dev-tools/backends/cargo.md
• RUSTC_WRAPPER= cargo test --bin mise backend::cargo::tests

[gemini-code-assist]

Code Review

This pull request refactors the Cargo backend to more intelligently decide between using cargo-binstall and cargo install based on the provided tool options. It introduces a BinstallStatus enum to manage these states and updates the documentation to reflect how options like features and default-features trigger a fallback to source builds. Feedback from the review suggests including the locked option in installation and lockfile resolution keys to ensure consistent behavior, skipping cargo-binstall when a custom registry is specified due to lack of CLI support, and adding the crate option to the list of settings that require a cargo install fallback to avoid potential argument conflicts.

[greptile-apps]

Greptile Summary

This PR fixes the cargo backend to fall back to cargo install (instead of using cargo-binstall) when tool options like features or default-features = false require a source build. It also tracks crate and locked in the lockfile options and documents the cargo-binstall compatibility for each tool option.

• Introduces a BinstallStatus enum (Enabled, Disabled, Unavailable, UnsupportedOptions) replacing the old boolean is_binstall_enabled helper, with a match-arm dispatch in install_version_ that correctly handles all binstall_only combinations.
• Extends lockfile_options and install_time_option_keys to include crate and locked, and adds four unit tests covering the new logic.
• Adds a compatibility table and per-option notes in the docs and settings.toml description explaining which options bypass cargo-binstall and that mise does not retry with cargo install after a binstall failure.

Confidence Score: 4/5

Safe to merge; the core install logic is correct for all documented cases and well-tested.

The only concern is a priority-inversion in binstall_status: unsupported options are detected before the cargo-binstall availability check, so a user with binstall_only=true, no cargo-binstall installed, and features set gets a misleading hint. This affects only an unusual combination of settings with no correctness impact.

src/backend/cargo.rs — specifically the ordering of checks in binstall_status

Important Files Changed

Filename	Overview
src/backend/cargo.rs	Refactors binstall logic into a BinstallStatus enum with a match arm dispatch; adds cargo_install_required_options helper; extends lockfile_options and install_time_option_keys with crate and locked; adds four unit tests. Logic is correct for all main paths; minor priority inversion in binstall_status (options checked before availability).
docs/dev-tools/backends/cargo.md	Adds a compatibility table and per-option notes clarifying which options skip cargo-binstall and which do not; content is accurate relative to the code changes.
settings.toml	Expands the cargo.binstall setting description to clarify that build settings don't apply to pre-built binaries and that mise does not retry with cargo install after a binstall failure.

_{Reviews (4): Last reviewed commit: "fix(cargo): skip binstall for cargo inst..." | Re-trigger Greptile}