feat: add MeasurementDetailScreen, 365-day charts, and edit support

- New MeasurementDetailScreen with wijzigen/verwijderen
- WeightChart now supports 30 and 365 days
- NewMeasurementScreen now handles both create and edit
- Updated README to match current code
- Add build-toolchain documentation
- Ignore *.apk build artifacts

.gitignore

@@ -111,6 +111,12 @@ test/fixtures/
 test/sample-pdfs/
 test/output/
 
+# Expo
+.expo/
+
+# APK builds
+*.apk
+
 # Temporary files
 temp/
 tmp/