Add pristine dotnet new webapi scaffold

Baseline commit of the untouched template so the M0 restructure lands as a
reviewable diff rather than appearing as the initial state.

Includes .gitignore and .gitattributes only; no source changes.

.gitignore

@@ -0,0 +1,92 @@
+## Build results
+[Bb]in/
+[Oo]bj/
+[Oo]ut/
+[Ll]og/
+[Ll]ogs/
+artifacts/
+!artifacts/openapi/
+!artifacts/schema/
+
+## .NET / MSBuild
+*.user
+*.suo
+*.userosscache
+*.sln.docstates
+project.lock.json
+project.fragment.lock.json
+*.binlog
+*.nuget.props
+*.nuget.targets
+msbuild.log
+msbuild.err
+msbuild.wrn
+
+## NuGet
+*.nupkg
+*.snupkg
+.nuget/
+**/packages/*
+!**/packages/build/
+# packages.lock.json IS committed — restore --locked-mode depends on it
+
+## Test / coverage
+[Tt]est[Rr]esult*/
+coverage*.json
+coverage*.xml
+coverage*.info
+*.coverage
+*.coveragexml
+TestResults/
+BenchmarkDotNet.Artifacts/
+
+## IDEs
+.vs/
+.vscode/*
+!.vscode/extensions.json
+!.vscode/launch.json
+!.vscode/tasks.json
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries/
+.idea/**/shelf/
+.idea/**/contentModel.xml
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/httpRequests/
+*.DotSettings.user
+
+## OS
+.DS_Store
+Thumbs.db
+desktop.ini
+
+## Node (xterm.js bundle in DodoSSH.Client.WebAssets)
+node_modules/
+npm-debug.log*
+yarn-error.log*
+.pnpm-store/
+
+## Client build / packaging output
+publish/
+Releases/
+*.AppImage
+*.dmg
+*.deb
+*.rpm
+*.msix
+*.appinstaller
+
+## Secrets and local config — never commit these
+*.pfx
+*.p12
+*.snk
+appsettings.Local.json
+appsettings.*.Local.json
+.env
+.env.*
+!deploy/.env.example
+secrets/