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>

docs/architecture/iptvnator-ui-guidelines.md

@@ -700,6 +700,27 @@ Settings use the same system but are flatter than content-heavy views.
   `EpgProgrammeDialogService` opens the programme dialog at 540px from the
   timeline, list, guide and channel rows, with a panel class that scopes its
   surface overrides.
+- **Destructive actions.** Material only emits `warn` button colors for M2
+  themes, so the `color` input is a no-op here. A button that removes or
+  discards user data uses the global `.app-destructive-button` class from
+  `m3-theme.scss` (error/on-error tokens per theme, for filled, text,
+  outlined and icon buttons), as the unsaved-changes dialog's Discard does.
+  Confirmations go through `DialogService.openConfirmDialog` with a
+  translated verb as the required `confirmLabel` ("Remove playlist",
+  "Clear") and `tone: 'destructive'` when the action loses data; the dismiss
+  defaults to "Cancel". Never confirm with "Yes"/"No". When the verb itself
+  is "Cancel …", pass `cancelLabel` "Close" so the two buttons do not read
+  alike. `theme-tokens.e2e.ts` checks the label and the error fill in both
+  themes.
+
+## Source Type Icons
+
+`SOURCE_TYPE_ICONS` in `@iptvnator/shared/interfaces` is the only source of
+provider icons: Xtream `cloud`, Stalker `cast`, the M3U family
+`playlist_play`, and per playlist `link` (URL), `description` (local file or
+text) and `subject` (pasted text in the add flow). Use
+`getPlaylistSourceIcon()` for a stored playlist. An icon never stands for two
+providers, and the Dashboard rail icon is never a provider icon.
 
 ## Phone Layout