feat: initialize WinUI 3 WebView migration

.gitattributes

@@ -0,0 +1,24 @@
+* text=auto
+
+.gitattributes text eol=lf
+.gitignore text eol=lf
+
+*.cs text eol=crlf
+*.sln text eol=crlf
+*.csproj text eol=crlf
+*.xaml text eol=crlf
+*.xml text eol=crlf
+*.appxmanifest text eol=crlf
+*.manifest text eol=crlf
+*.pubxml text eol=crlf
+*.json text eol=lf
+*.html text eol=lf
+*.css text eol=lf
+*.js text eol=lf
+*.md text eol=lf
+
+*.png binary
+*.ico binary
+
+# The migrated SQL files preserve legacy verbatim-query formatting.
+src/MBN_STOCK_WEBVIEW.Core/LegacyData/** whitespace=-blank-at-eol,-blank-at-eof,-space-before-tab