Refactor and enhance type safety across various modules

- Updated function parameters and return types in `page-preview.ts`, `pdf-decrypt.ts`, and `pymupdf-loader.ts` for improved type safety.
- Introduced type definitions for `CpdfInstance`, `PyMuPDFInstance`, and other related types to ensure better type checking.
- Enhanced error handling in `sanitize.ts` by creating a utility function for error messages.
- Removed unnecessary type assertions and improved type inference in `editor.ts`, `serialization.ts`, and `tools.test.ts`.
- Added type definitions for markdown-it plugins to improve compatibility and type safety.
- Enforced stricter TypeScript settings by enabling `noImplicitAny` in `tsconfig.json`.
- Cleaned up test files by refining type assertions and ensuring consistency in type usage.

tsconfig.json

@@ -42,7 +42,7 @@
     "noFallthroughCasesInSwitch": false,
     "noUncheckedSideEffectImports": false,
     /* Fix for ArrayBuffer type issues */
-    "noImplicitAny": false,
+    "noImplicitAny": true,
     /* Quality-of-life options */
     "isolatedModules": true,
     "esModuleInterop": true,