Always apply headers to localhost requests, overriding any configured scopes

New Features
- URL filter bar — Filter the header list by URL scope to quickly find scoped headers
- Global tab wizard — Batch-target multiple headers to a specific URL via a guided flow
- Drag & drop URL targeting — Reassign a header's URL target by dragging it to a new scope

Improvements
- Consistently match scoped headers against domains, subdomains, paths, and wildcards
- Group headers on the URL-specific tab by their exact scoped URL
- Reuse previously used URLs via the new Select component when targeting a header
- Focus the header key input automatically after creating a new header
- Clearer empty states for the header list
- Prominent alert on the Global tab clarifying that those headers apply everywhere
- New Toast component — saving header info now gives instant feedback

Add option to use labels for headers

Bugfix: Headers were not applied to the requests

Bugfixes:

• Make sure existing headers also have a unique ID

Contains the following bugfixes & feature:

• Remove cross-bundle import so background script is self-contained
• Fix disabling the extension in settings
• Use React compiler