fix: FilePreview fileType case + Tailwind v4 gradient transparent bug

- FilePreview.vue: add normalizedFileType computed to handle backend
  returning uppercase HTML/MD/PPTX (fixes preview/download buttons)
- FilePreview.vue: bg-gradient-to-r from-orange-500 -> bg-orange-500
  (Tailwind v4 gradient + CSS variable = transparent)
- ReportCard.vue: bg-gradient-to-r -> bg-orange-600 for selected state
- Add .opencode/, node_modules/, dist/ to .gitignore
- Initial git setup for publish project

Dockerfile

@@ -0,0 +1,15 @@
+# Backend: Pre-built JAR
+FROM eclipse-temurin:26.0.1_8-jre-noble
+WORKDIR /app
+
+# Create uploads directory with write permissions
+RUN mkdir -p /app/uploads && chmod -R 777 /app/uploads
+
+# Copy pre-built JAR (v7 - renamed to break cache)
+COPY target/app-v7.jar app-v7.jar
+
+# Expose port
+EXPOSE 8080
+
+# Run the application
+ENTRYPOINT ["java", "-jar", "app-v7.jar"]