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

.dockerignore

@@ -0,0 +1,40 @@
+# Exclude build artifacts and dependencies
+node_modules
+dist
+target
+
+# Exclude IDE and system files
+.git
+.mavis
+.mvn
+.opencode
+
+# Exclude test and dev files
+test-results
+test-uploads
+tests
+*.spec.js
+*.test.js
+
+# Exclude unnecessary config files (frontend is pre-built)
+*.bat
+*.ps1
+playwright.config.js
+vitest.config.js
+postcss.config.*
+tsconfig.json
+tsconfig.node.json
+vite.config.js
+tailwind.config.js
+package.json
+package-lock.json
+src
+
+# Exclude local files
+database.db
+*.zip
+*.log
+*.txt
+spawn-config.json
+team-plan.yaml
+worker1.json