Add hybrid versioning scripts, version shown in app footer

.gitignore

@@ -17,6 +17,10 @@ yarn-error.log*
 /build
 /dist
 
+# Version files (auto-generated by prebuild script)
+/src/version.ts
+/src/version.json
+
 # IDE
 .vscode/
 .idea/
@@ -36,6 +40,10 @@ yarn-error.log*
 /public/static/
 /hint-report/
 
+# Temp files and custom exclude patterns
 ~*
 \#*
 _*
+
+# project specific
+src/version.json