## Summary

First branch of the 0.4 cycle. Bumps every TargetFramework from `net9.0`
→ `net10.0`, renames the demo folder `NET9/` → `NET10/`, migrates the
solution to the new `.slnx` XML format, removes the
`EnableStaticWebAssetsCompression=false` workaround (the .NET 10 SDK
fixed the underlying bug), and bumps the centralized version to
`0.4.0-alpha.1`.

Single-target `net10.0` for simplicity. `net9.0` STS reaches EOL this
month; `net8.0` LTS users can stay on the `0.3.x` line until they
upgrade. If enterprise demand justifies it later, we can multi-target
`net8.0;net10.0` in a follow-up before 1.0.

C# 14 modernization (`field` keyword, partial constructors, extension
members, etc.) is intentionally **not** in this branch — it'll get its
own dedicated `chore/csharp14-sweep` branch later so the diff is
reviewable.

## Changes

### Framework + tooling
- `global.json` — SDK pin `9.0.100` → `10.0.100`
- `Directory.Build.props` — `0.3.0-rc.1` → `0.4.0-alpha.1`
- All 5 first-party `.csproj`s (`Core`, `Templates`, `CLI`,
`Components`, `Tests`) — `<TargetFramework>net9.0</TargetFramework>` →
`net10.0`
- Both demo `.csproj`s (`BlazorInteractiveServer`, `ShellUI.Preview`) —
same TFM bump
- `Microsoft.AspNetCore.Components.Web` package ref `9.0.6` → `10.0.0`
(Components)
- `Microsoft.AspNetCore.Components.WebAssembly` and `.DevServer` `9.0.0`
→ `10.0.0` (Preview)
- `IntegrationTest1.cs` — hardcoded CLI build path `bin/Release/net9.0/`
→ `bin/Release/net10.0/`

### Solution format migration
- `ShellUI.sln` removed, `ShellUI.slnx` generated via `dotnet sln
ShellUI.sln migrate`. Cleaner XML, much more diffable, no copy-paste
risk:
  ```xml
  <Solution>
    <Configurations>
      <Platform Name="Any CPU" />
      <Platform Name="x64" />
      <Platform Name="x86" />
    </Configurations>
    <Folder Name="/src/">
      <Project Path="src/ShellUI.CLI/ShellUI.CLI.csproj" />
<Project Path="src/ShellUI.Components/ShellUI.Components.csproj" />
      <Project Path="src/ShellUI.Core/ShellUI.Core.csproj" />
      <Project Path="src/ShellUI.Templates/ShellUI.Templates.csproj" />
    </Folder>
    <Project Path="ShellUI.Tests/ShellUI.Tests.csproj" />
  </Solution>
  ```
- All CI workflow `dotnet restore|build|test|pack ShellUI.sln`
invocations updated to `ShellUI.slnx`

### Demo folder rename
- `NET9/` → `NET10/` (`git mv`, preserves history per the rename
detector). Updated the preview-pages workflow path filters and publish
step accordingly.

### .NET 10 SDK fixed our workaround
- `ShellUI.Components.csproj` —
`<EnableStaticWebAssetsCompression>false</EnableStaticWebAssetsCompression>`
and the `<StaticWebAssetsBuildMode>` line are gone. The original comment
said "(.NET 10 SDK bug workaround)" — confirmed by `dotnet pack` working
clean without them.

### CI workflows
- `.github/workflows/ci.yml` — `dotnet-version: 9.0.x` → `10.0.x`,
`.sln` → `.slnx`
- `.github/workflows/release.yml` — same
- `.github/workflows/preview-pages.yml` — same +
`NET9/ShellUI.Preview/**` path filter → `NET10/ShellUI.Preview/**`

### Docs
- `docs/PROJECT_STATUS.md` — prerequisite `.NET 9.0 SDK` → `.NET 10.0
SDK`, demo path `NET9/BlazorInteractiveServer` → `NET10/`, "Key Decision
#4" rewritten to explain why .NET 10 single-target instead of
multi-target
- `docs/ARCHITECTURE.md` — `NET9/` → `NET10/`
- `docs/tailwind-setup.md` — `.NET 9.0 SDK` → `.NET 10.0 SDK`

## Verification

- `dotnet restore ShellUI.slnx` — clean, all packages resolved on .NET
10
- `dotnet build ShellUI.slnx -c Release` — clean (0 errors, 0 warnings),
packages emitted as `0.4.0-alpha.1.nupkg`
- `dotnet test ShellUI.Tests` — **51/51 unit tests passing on
`net10.0`** (skipping the 2 slow CLI integration tests that need
scaffolded projects — those will run in the CI smoke step)
- `dotnet pack src/ShellUI.Components` without the workaround — clean
pack succeeds; confirms .NET 10 SDK fixed the bug

## Test plan

- [ ] CI green on .NET 10 — build, all unit tests, end-to-end smoke
(scaffold + `shellui init` + `shellui add chart pie-chart dashboard-02
data-table` + `dotnet build` on a real `dotnet new blazor` template)
- [ ] Local: `dotnet new blazor` (which now generates a .NET 10 project)
+ install the prerelease CLI tool from this branch's pack + `shellui
init` + `shellui add` — confirm it still works end-to-end against the
new template
- [ ] Local: open `ShellUI.slnx` in VS 2022 17.10+ and confirm the
solution loads correctly
- [ ] Verify `Blazor-ApexCharts 6.0.2` and `System.Linq.Dynamic.Core
1.7.1` work on .NET 10 (they multi-target down to
`net6.0`/`netstandard2.0`, so they should be fine via roll-forward — the
build success above already proves the resolver picks them up)