Include tag counts in tag filter & tag input autocomplete

[emma-sg]

This PR is currently targeting #2702 to show the differences made, but doesn't need to be merged into it — I can rebase from main and implement this as a fast-follow instead, since this touches both frontend and backend.

Changes

• Adds a new /api/orgs/{oid}/crawlconfigs/tagCounts endpoint that returns { tags: { tag: string, count: number }[] }
• Deprecates /api/orgs/{oid}/crawlconfigs/tags endpoint
• Updates workflow tag filter & tag input suggestion dropdown to display tag counts from new endpoint
• Updates <btrix-badge> to include pill, outline, and variant="blue" properties
  • The existing implementation didn't fit these use cases, and <btrix-tag> comes with the extra behaviour around deletion etc
• Hides existing tags from tag input suggestion dropdown
• Fixes tag input dropdown z-index bug

Manual testing

1. On an org with multiple workflows, on the workflow page test that tag filters work as expected & are sorted by [tag count, tag name]
2. Edit a workflow or archived item. In the Metadata section, check that tag autocomplete shows existing tag counts when you start typing, and also that it doesn't show tags in the autocomplete that are already in the tag input

Screenshots

Page	Image/video
Workflow tag filter dropdown

Tag input suggestion dropdown:

Screen.Recording.2025-07-02.at.8.01.31.PM.mov

[SuaYoo]

Great enhancement!