## Summary

Replaces the experimental conda backend's ~1,625 lines of custom code
with the [rattler](https://github.com/conda/rattler) Rust crates — the
same crates that power [pixi](https://github.com/prefix-dev/pixi).
Motivated by [jdx#8318](jdx#8318) from
a conda maintainer who noted the backend was directly using the
unsupported `api.anaconda.org` API.

**What was replaced:**
- Custom version matching and comparison logic
- Recursive dependency resolution via raw anaconda.org API calls
- Manual `.conda` ZIP+tar.zst and `.tar.bz2` extraction
- Hardcoded `SKIP_PACKAGES` list for virtual packages
- Custom patchelf/install_name_tool/codesign binary patching
(`conda_common.rs`, `conda_linux.rs`, `conda_macos.rs` deleted)

**With rattler:**
- `rattler_repodata_gateway` — fetches repodata from conda channels
(proper CDN-cached repodata.json)
- `rattler_solve` (resolvo) — SAT-based dependency solver, same as used
by pixi/conda-libmamba
- `rattler_package_streaming` — extracts `.conda` and `.tar.bz2`
archives
- `rattler_virtual_packages` — detects system virtual packages
(`__glibc`, `__osx`, etc.) properly
- `rattler::install::link_package` — proper conda installation with text
AND binary prefix replacement, file permissions, and macOS codesigning

**Key fix:** The old code explicitly skipped binary files during prefix
replacement (checking for null bytes). `link_package` correctly handles
binary prefix replacement by padding with null bytes to preserve byte
length, which is how conda is designed to work.

**Kept unchanged:**
- `lockfile.rs` — `CondaPackageInfo` type and `[conda-packages]` TOML
format
- All registry entries and settings

Since `EXPERIMENTAL = true`, breaking changes are acceptable.

## Test plan

- [x] `cargo build` — compiles cleanly
- [x] `mise run test:unit` — 481 tests pass
- [x] `mise run lint` — all checks pass
- [x] `mise run test:e2e test_conda`:
  - `conda:ruff@0.8.0` — installs with 24 deps, runs correctly
  - `conda:bat@0.24.0` — installs with 4 deps, runs correctly
  - `conda:jq@1.7.1` — installs with deps (oniguruma), runs correctly
  - `conda:postgresql@17.2` — installs with 29 deps, runs correctly
- [x] `mise lock` — lockfile generated correctly with per-platform deps

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Large rewrite of conda install/solve behavior (networking, dependency
resolution, and prefix handling) that could change which packages get
installed or how they’re linked; mitigated somewhat by being confined to
the experimental conda backend and adding checksum-verified,
lockfile-driven installs.
> 
> **Overview**
> Switches the experimental `conda` backend from bespoke anaconda.org
API calls, ad-hoc version/dependency selection, and manual archive
extraction/prefix patching to the `rattler` ecosystem:
`rattler_repodata_gateway` for repodata retrieval/caching,
`rattler_solve` (resolvo) for dependency solving with virtual package
detection, and `rattler::install::link_package` +
`rattler_package_streaming` for extraction and correct text/binary
prefix replacement.
> 
> Lockfile behavior is preserved but now populated from solver
`RepoDataRecord`s (URLs + sha256) and can perform deterministic installs
by downloading the locked URL set with checksum verification; Windows
bin path discovery is broadened to include both `Library/bin` and `bin`.
The previous platform-specific patching modules (`conda_common.rs`,
`conda_linux.rs`, `conda_macos.rs`) are removed, and Cargo
dependencies/lockfile are updated to include the new `rattler*` crates
and transitive deps.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
21d3602. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

## Summary
- Adds a native core plugin for .NET SDK that installs all versions
side-by-side under a shared `DOTNET_ROOT`, matching .NET's native
multi-version model
- Supports `global.json` as an idiomatic version file for per-project
SDK pinning
- Uses Microsoft's official `dotnet-install.sh`/`.ps1` script for
installation, with cross-platform support

## Motivation
Closes discussion jdx#7939 — users need multiple .NET SDK versions
installed simultaneously for multi-targeting (e.g., net6.0 + net8.0 in
one solution). The existing vfox-based plugin installs each version in
isolation, breaking .NET's native side-by-side model.

## Changes
- **`src/plugins/core/dotnet.rs`** — Core plugin implementation (version
listing from Microsoft releases API, install via official script, shared
DOTNET_ROOT, global.json parsing)
- **`src/plugins/core/mod.rs`** — Register the new plugin
- **`registry/dotnet.toml`** — Add `core:dotnet` as primary backend
(vfox/asdf remain as fallbacks)
- **`settings.toml`** — Add `dotnet.dotnet_root` setting
(`MISE_DOTNET_ROOT` env)
- **`docs/lang/dotnet.md`** — Documentation
- **`e2e/core/test_dotnet`** — E2E smoke test
- **`schema/mise.json`** — Auto-generated schema update

## Test plan
- [x] `mise run render` — regenerated settings struct, schema,
completions
- [x] `mise run lint-fix` — all linters pass
- [x] `mise run build` — compiles cleanly
- [x] `mise run test:unit` — all 481 tests pass
- [ ] `mise run test:e2e test_dotnet` — installs dotnet@8.0.408,
verifies version, tests global.json
- [ ] Manual: `mise use dotnet@8 && mise use dotnet@9 && dotnet
--list-sdks` shows both

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Adds a new core installer that downloads and executes the upstream
`dotnet-install` script and changes the default backend resolution for
`dotnet`, which could affect installs/uninstalls and environment setup
across platforms.
> 
> **Overview**
> Adds a new **core** `dotnet` tool plugin that installs .NET SDKs via
Microsoft’s official `dotnet-install` script and lists available SDK
versions from the Microsoft releases metadata API.
> 
> Introduces a shared `DOTNET_ROOT` install model by default (with
symlinked per-version install paths for tracking), plus an opt-in
`dotnet.isolated` mode for per-version directories; the plugin also
supports `global.json` as an idiomatic version file and sets
`DOTNET_MULTILEVEL_LOOKUP` and optional `DOTNET_CLI_TELEMETRY_OPTOUT`.
> 
> Makes `core:dotnet` the first backend in `registry/dotnet.toml`, adds
new settings (`dotnet.dotnet_root`, `dotnet.isolated`,
`dotnet.cli_telemetry_optout`) to `settings.toml`/schema, and includes
docs + an e2e smoke test for install and `global.json` resolution.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
e35fbbe. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>