fix(dotnet): use shared prerelease tool option

[risu729]

Summary

• make the dotnet backend fetch the NuGet prerelease superset and use the shared prerelease filtering path used by github/aqua
• add prerelease = true support for dotnet while keeping the existing global prereleases setting and deprecated dotnet.package_flags = ["prerelease"] compatibility
• skip aqua/github latest fast paths when prereleases are enabled so latest resolves from the full prerelease-aware version list
• update docs, e2e coverage, and generated schemas

Testing

• cargo fmt --all -- --check
• /home/risu/.cargo/bin/cargo test test_include_prereleases --bin mise
• markdownlint docs/dev-tools/backends/aqua.md docs/dev-tools/backends/dotnet.md docs/dev-tools/backends/github.md
• mise run render:schema
• PATH=/home/risu/.cargo/bin:$PATH mise run test:e2e e2e/backend/test_dotnet
• manual: MISE_EXPERIMENTAL=1 ./target/debug/mise ls-remote dotnet:GitVersion.Tool does not show beta versions after a prerelease cache fill
• manual: MISE_EXPERIMENTAL=1 ./target/debug/mise ls-remote "dotnet:GitVersion.Tool[prerelease=true]" shows beta versions
• manual: MISE_EXPERIMENTAL=1 MISE_DOTNET_PACKAGE_FLAGS=prerelease ./target/debug/mise ls-remote dotnet:GitVersion.Tool shows beta versions

This PR was generated by an AI coding assistant.

[gemini-code-assist]

Code Review

This pull request standardizes the prerelease tool option across the aqua, github, and dotnet backends, deprecating the legacy plural prereleases spelling and the dotnet.package_flags = ["prerelease"] setting. The dotnet backend was refactored to simplify version listing by leveraging the base trait's filtering logic, and documentation, tests, and JSON schemas were updated to reflect these changes. I have no feedback to provide as there were no review comments.

[greptile-apps]

Greptile Summary

This PR refactors the dotnet backend to always fetch the full NuGet prerelease superset (prerelease=true) and apply a read-time filter, matching the caching pattern already used by the GitHub and Aqua backends. It also promotes include_prereleases from a free function to a Backend trait method, lets DotnetBackend override it to add legacy dotnet.package_flags compatibility, and deprecates that legacy setting in favour of the per-tool prerelease = true option.

• _list_remote_versions in DotnetBackend now unconditionally passes prerelease=true to NuGet and relies on mark_prereleases_from_version_pattern + filter_cached_prereleases for read-time filtering, removing the previous custom cache-bypass override.
• include_prereleases is a new Backend trait method with a shared default implementation; DotnetBackend, AquaBackend (latest_stable_version fast-path guard), and UnifiedGitBackend are all updated to use it.
• dotnet.package_flags is marked deprecated with warn_at = 2026.11.0 and remove_at = 2027.11.0; docs, schema, and e2e tests are updated accordingly.

Confidence Score: 5/5

Safe to merge — the refactor is well-scoped and the NuGet-always-prerelease approach correctly delegates filtering to the shared cache path used by every other backend.

The core change (always fetching the NuGet prerelease superset and filtering at read time) is a straight port of the pattern that already works for GitHub and Aqua. The trait-method promotion of include_prereleases is mechanical and all call sites are updated. Deprecation dates in settings.toml, the deprecated_at! call, and the schema annotation are all consistent. No behavioural regressions were found on the filtering, caching, or latest-resolution paths.

No files require special attention.

Important Files Changed

Filename	Overview
src/backend/dotnet.rs	Core dotnet refactor: always fetches NuGet with prerelease=true, removes custom cache bypass, overrides include_prereleases for legacy flag compat, adds dotnet_legacy_prerelease_package_flag_enabled helper. Logic is sound.
src/backend/mod.rs	Promotes include_prereleases to a trait method with default impl, adds tool_option_bool module-level helper, migrates existing call sites, adds TestBackend for unit tests. All changes are consistent and correct.
src/backend/aqua.rs	latest_stable_version now skips the fast path when prereleases are enabled, matching the pattern already used by the github backend.
src/backend/github.rs	Switches from the removed free function include_prereleases to the new self.include_prereleases trait method. Mechanical and correct.
src/backend/conda.rs	Switches from the removed free function include_prereleases to self.include_prereleases. Drops now-unused import. Mechanical and correct.
settings.toml	Adds deprecation metadata (warn_at 2026.11.0, remove_at 2027.11.0) and updated docs to dotnet.package_flags; the dates align with the deprecated_at! call in code.
e2e/backend/test_dotnet	Adds coverage for prerelease=true tool option and scopes the legacy env-var test inline rather than exporting it globally. Cache-clear steps are correctly placed between runs.
docs/dev-tools/backends/dotnet.md	Documents the new prerelease tool option and the migration path away from the deprecated package_flags setting; accurately describes the global/per-tool interaction.
schema/mise.json	Marks dotnet.package_flags as deprecated in JSON Schema (deprecated: true, updated description). Consistent with settings.toml changes.

_{Reviews (5): Last reviewed commit: "refactor(backend): fold prerelease optio..." | Re-trigger Greptile}