Add tag management to template screens

[rhys-vultron]

Summary

Template tags are a core feature of E2B (docs) but there's currently no way to manage them from the dashboard. Users have to use the SDK to assign/remove tags.

Proposed Changes

• Display tags as badges in the templates list table
• Add inline tag management (assign/remove) via a popover UI on each row
• Add a tag filter to the existing filter bar
• Wire up the existing infra API endpoints (POST /templates/tags, DELETE /templates/tags, GET /templates/{templateID}/tags)

Benefits

• Users can view and manage template tags without leaving the dashboard
• Consistent with existing table patterns (filters, badges, inline actions)

[linear]

ENG-3587

[rhys-vultron]

Closing for now - prototype in PR #282.