feat(ui): expand funnel filter options

[fl0rianr]

Summary

Adds compact custom filtering to the Models tab funnel menu in the GUI3 prototype.

Why

The model list is growing, so users need a quick way to find or hide model groups without relying only on predefined capability filters. This is especially useful for excluding models by keyword, for example hiding all models containing qwen.

Changes

• Adds custom text filter rules to the Models tab.
• Supports combining multiple filter rules.
• Supports include and exclude matching through compact icon toggles.
• Allows filtering by:
  • any searchable text
  • model name
  • backend
  • type
  • capability
  • label
  • status
• Keeps existing capability filters intact.
• Moves the popover into an overlay position so it can expand beyond the rail instead of being clipped.

Testing

• Verified npm run build succeeds
• npm test yields 7 skipped 195 passed
• locally checked and tested for function