Adding support for .slns, among other enhancements

[haondt]

This is a pretty big change, feel free to close the PR if you're not interested. I have no intention of breaking up this change (I can make additional changes/fixes if needed), but felt I should at least offer to contribute back. It started with a smaller change and kind of spiralled.

Changes:

• moved the search to an async picker (based off of this gist), to live-search for packages
• uses the dotnet cli for all operations. This has the benefit of respecting the users NuGet.Config when searching packages
• enhanced the package picker to show if packages are outdated or contain mixed versions in different csprojs
• enhanced the version picker to show the currently used version(s) and the latest version
• added some tooling to customize the search, namely including prerelease packages and specifying nuget sources
• added support for multiple .csproj and .sln files.
• added support for fidget.nvim to show progress updates

I believe it also addresses some, but not all of the concerns in #1. It can update and consolidate multiple csprojs under the same solution, but some more work would need to be done to install a package on discrete projects.

[d7omdev]

Hey @haondt, this is really cool, thanks for putting this together. The async live-search alone is a huge UX improvement over the old input prompt approach, Glad you decided to share it.

I went through everything carefully and found a few bugs worth fixing before I merge:

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Bug 1 — version aggregation picks the lowest, not the highest (dotnet.lua lines 96, 173, 211, 261)

After table.sort(versions, utils.version_lt) the list is ascending, so versions[1] is the lowest version. The annotation says it should be the highest — fix is just
changing it to versions[#versions].

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Bug 2 — crash in the remove failure path (pickers/csproj.lua:69)

notify.show_error_float("Failed: " .. package .. " " .. sel.value, ...)

package isn't in scope here, it resolves to Lua's own built-in package table and blows up with a concatenation error. Should be sel.value.id.

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Bug 3 — other_cnt is off (pickers/nuget.lua:246)

local other_cnt = #projs -- already the full count
...
other_cnt = other_cnt + 1 -- then keeps adding

Say a package is in 3 projects and you're targeting 1 of them — the badge ends up showing (5) instead of (2). Starting other_cnt at 0 fixes it.

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Bug 4 — build_project_map always calls bare dotnet (dotnet.lua:516)

vim.fn.systemlist("dotnet sln " .. vim.fn.shellescape(...) .. " list")

Whatever the user set for dotnet_bin gets ignored here. Also worth noting that this function has a hard dependency on fd with no fallback — if it's not installed the
picker just silently shows nothing.

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Bug 5 — is_sln never actually set (pickers/projects.lua:54)

The display function checks et.is_sln to pick the highlight, but nothing ever sets it on the entry. Adding is_sln = filetype == "sln" to the entry table is all it needs.

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Smaller things I noticed:

• vim.loop is deprecated since Neovim 0.10, vim.uv is the way to go now (async_finder.lua:14)
• Remove only works on individual .csproj files right now — remove.lua hardcodes opts.filter = "csproj" so there's no solution-wide remove yet
• dotnet package search needs .NET 8+ — probably worth a line in the README so people on older SDKs aren't confused

Bugs 1–5 are the ones I'd want fixed before merging, the rest can be follow-ups. Let me know if anything's unclear
and sorry for the late reply, was on holiday!