ci: run the test job on its own inputs and trim its checkout (#10016)

Follow-ups to #10007, none of which change what the test command does.

The `paths:` filter listed individual source folders rather than the
projects the suite builds, so a change anywhere else in that build
produced no check at all. Of the last 40 merged pull requests, 31 touch
the test build and 15 of those ran no tests. #9976 and #9932 edit
`ServiceLib/Common/`, which every test depends on, and neither shows a
single check. `Directory.Build.props` is the sharpest case: it sets
`TargetFramework` and the Release options for every project, so an edit
there can break the test build without producing a workflow run at all.

The filter now follows the project graph instead. `ServiceLib.Tests`
references `ServiceLib`, which references `ServiceLib.UdpTest`, and
`Directory.Build.*`, `Directory.Packages.props` and `global.json`
configure that build. It is shorter than the list it replaces, needs no
edit when a test is added or a class moves, and still skips UI and
documentation work: of those same 40 pull requests, 9 stay filtered out.

`global.json` belongs there for a different reason: it does not affect a
single line of the code under test, but it decides whether the tests run
at all, so a bad edit there silently reproduces the failure #10007 fixed.

The Checkout step needs neither `submodules: 'recursive'` nor
`fetch-depth: '0'`. `GlobalHotKeys` is pulled in by `v2rayN.Desktop`
only, and nothing in this job reads git history.

`global.json` also gained the final newline `.editorconfig` asks for with
`insert_final_newline = true` under `[*]`.

.github/workflows/test.yml

@@ -5,8 +5,12 @@ on:
     branches:
       - master
     paths:
-      - 'v2rayN/ServiceLib/Services/CoreConfig/**'
-      - 'v2rayN/ServiceLib/Handler/Fmt/**'
+      - 'v2rayN/ServiceLib/**'
+      - 'v2rayN/ServiceLib.UdpTest/**'
+      - 'v2rayN/ServiceLib.Tests/**'
+      - 'v2rayN/Directory.Build.*'
+      - 'v2rayN/Directory.Packages.props'
+      - 'global.json'
       - '.github/workflows/test.yml'
 
 permissions:
@@ -19,9 +23,6 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v7
-      with:
-        submodules: 'recursive'
-        fetch-depth: '0'
 
     - name: Setup .NET
       uses: actions/setup-dotnet@v6