fix(a11y): accessible names for icon-only buttons and a guard (#1880)

* fix(a11y): accessible names for icon-only buttons and a guard

Icon-only buttons named only by a matTooltip (or by nothing) had no
accessible name: the icon ligature is hidden from assistive technology
and a tooltip only adds a description. 22 buttons on master, in .html
and inline templates, now carry a translated aria-label bound to their
tooltip key. The channel row's favorite star keeps one label
("Favorite") and reports its state through aria-pressed.

New guard `pnpm run a11y:icon-buttons:validate` (CI step) fails on a
<button> whose only content is mat-icons (through control flow,
ng-container and spinners) without aria-label, an aria-label binding
or aria-labelledby. The inline-template lookup moves to a shared
tools/nx/inline-templates.mjs used by the icon-ligature guard too.

web-e2e icon-button-names.e2e.ts runs axe's button-name rule on a
channel list, the channel details dialog, Sources, the playlist info
dialog and an Xtream search. Five new keys are translated in all 18
locales.

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

* fix(a11y): text hidden from assistive technology never names an icon button

Greptile: a static aria-hidden="true" child's text counted as the
button's name, so <button><mat-icon/><span aria-hidden="true">Close</span>
passed the guard. Hidden subtrees now add only their icons.

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

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -416,6 +416,11 @@ jobs:
             - name: Validate Material icon names
               run: pnpm run styles:icon-ligatures:validate
 
+            # A tooltip is not an accessible name: an icon-only <button> needs
+            # aria-label, an aria-label binding or aria-labelledby.
+            - name: Validate icon-only button names
+              run: pnpm run a11y:icon-buttons:validate
+
             # Nx rejects a non-parallel task with continuous dependencies, and
             # the Playwright plugin infers serve dependencies only when CI is
             # unset, so this checks both the local and the CI inference.