fix(ui): destructive confirmations, verb labels and provider icons

Confirmations: ConfirmDialogData.confirmLabel is required, so no dialog can
fall back to "Yes"/"No"; the dismiss defaults to "Cancel" and
`tone: 'destructive'` styles the confirm with .app-destructive-button. Every
caller names its action ("Remove playlist", "Clear", "Refresh playlist",
"Cancel download" with a "Close" dismiss). The confirm button has the
confirm-dialog-confirm test id and drops its no-op color="primary".

The no-op `warn` color input becomes .app-destructive-button on the EPG
mapping, playlist item, error view, EPG/reset settings, delete-all and source
cleanup buttons, and on the unsaved-changes dialog's Discard.

Provider icons come from SOURCE_TYPE_ICONS in shared/interfaces (Xtream
cloud, Stalker cast, M3U playlist_play / link / description / subject) in the
add dialog, auto-import, empty state, playlist switcher, playlist rows,
dashboard source rail, command palette, Sources filters and both reset
summaries. Stalker no longer borrows the Dashboard icon, and Xtream no longer
shares a glyph with M3U URL playlists.

The playlist error view removed a playlist through the stale
PlaylistActions.removePlaylist: it dropped the playlist from state before the
delete ran, swallowed failures, skipped the source activity guard and showed
no toast. It now uses PlaylistDeleteActionService like every other removal,
commits only a completed delete, toasts and goes home. The unused action and
its effect are removed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.changes/ui-destructive-confirmations.md

@@ -0,0 +1,6 @@
+---
+type: fix
+area: ui
+---
+
+Removing or clearing data now asks with a named action on a red button instead of "Yes"/"No", and delete buttons are red again. Each source type has one icon everywhere. Deleting a playlist from its error screen now confirms with a message and keeps the playlist if the delete fails.