Refactor: Clean up and improve sample and pack management

Commit notes

This commit addresses several areas:

- **XO Feature Removal:** The "XO" (eXperimental Operations) related routes and queries have been removed. This includes endpoints for analyzing samples and finding similar samples using XO embeddings. The functionality for finding similar samples has been replaced with a more general library-based approach.

- **Tag Handling:** The way tags are handled has been standardized. Instead of comma-separated strings, tags are now consistently represented as arrays of strings across the backend and frontend. This improves data integrity and simplifies processing.

- **`isShared` Field Removal:** The `isShared` field has been removed from `collections` and `samples`. Sharing logic is now implicitly handled by checking for collaborators or public visibility.

- **Metadata Parsing:** JSON parsing for metadata fields (like `permissions` and `metadata` in activities) has been made more robust, defaulting to `null` if the data is missing or invalid.

- **Type Safety and Consistency:** Various minor improvements have been made to enhance type safety, code consistency, and readability throughout the codebase. This includes updating type definitions and ensuring consistent handling of optional fields.

- **Frontend Updates:** Corresponding frontend changes have been made to accommodate the backend modifications, particularly in how tags and sample data are processed and displayed.

These changes aim to streamline the codebase, improve data management, and remove experimental features that are no longer actively maintained.

Co-authored-by: armin.naimi <[email redacted]>