Migrated portlets: adopt Material Symbols (Rounded) as the sole icon style

Description

Adopt Material Symbols (Rounded) as the single icon style across every portlet migrated by Modernization. Currently these portlets ship a mix of icon systems (dominated by PrimeIcons pi pi-*), which drifts from the platform-wide design direction and produces an inconsistent UI over time.

Design requirement: Material Symbols Rounded, no exceptions.

Reference: https://fonts.google.com/icons?icon.style=Rounded

Scope

All portlets migrated by Modernization:

• dot-tags
• dot-query-tool
• dot-es-search
• dot-velocity-playground
• dot-publishing-queue
• dot-locales
• dot-categories
• dot-plugins

Acceptance Criteria

• The Material Symbols Rounded font is available application-wide (loaded once at the app shell / global stylesheet if not already present).
• Every icon in the portlets listed above uses material-symbols-rounded — no pi pi-* (PrimeIcons) references remain in those portlets.
• Semantic mapping is preserved when swapping icons, e.g.:
  • pi-play → play_arrow
  • pi-trash → delete
  • pi-download → download
  • pi-upload → upload
  • pi-chevron-down / pi-chevron-up → keyboard_arrow_down / keyboard_arrow_up
  • pi-exclamation-triangle → warning
  • pi-question-circle → help
  • pi-copy → content_copy
  • pi-search → search
  • pi-times-circle → cancel
  • pi-info-circle → info
  • pi-tags → sell
  • pi-lock → lock
• Where PrimeNG components accept an icon attribute (buttons, p-inputIcon, file upload triggers, etc.), use the PrimeNG idiom that supports custom icons (icon pTemplate slot, or content projection) so Material Symbols renders correctly inside PrimeNG shells.
• Existing accessibility attributes (aria-label, aria-hidden, [attr.aria-label]) are preserved on each icon element.
• Manual QA per portlet: toolbar, table row actions, empty states, dialogs, help/tooltip triggers, error/warning banners — no icon missing or broken.
• Existing material-symbols-outlined usages in the codebase (e.g. libs/portlets/edit-ema/ui/) are noted but out of scope for this ticket unless they belong to a listed migrated portlet.

Priority

Medium — design consistency across migrated portlets.

Additional Context

Reference: https://fonts.google.com/icons?icon.style=Rounded