style: theme-aware token pass for dark-mode surfaces (Phase 18)

Re-point neutral page surfaces, play-chip, and default popover from constant brand tokens to theme-aware aliases defined twice in deepdrft-tokens.css. Decorative navy/green sections and bespoke dark-glass panels untouched. Appbar-navy symptom deferred (palette C#, out of CSS scope).

DeepDrftPublic.Client/Controls/AudioPlayerBar/AudioPlayerBar.razor.css

@@ -42,6 +42,20 @@
     right: 0.5rem;
 }
 
+/* PLAYER-BAR play-chip override (Phase 18, T3). PlayStateIcon's chip defaults to the solid
+   --deepdrft-play-chip (moss-green in dark) used on release heroes and Cut track rows. On the
+   bright player dock that solid green reads too hot, so here — and only here — swap to the
+   translucent --deepdrft-play-chip-soft (same green, much less opaque). The glyph stays the
+   palette green/primary on this context (the navy default-glyph would vanish on the translucent
+   wash), so we let MudIconButton's own Color.Primary stand by neutralising the default override. */
+::deep .player-surface .icon-container {
+    background-color: var(--deepdrft-play-chip-soft);
+}
+
+::deep .player-surface .icon-container .mud-icon-button {
+    color: var(--mud-palette-primary);
+}
+
 /* Minimized floating dock — positioning + hover only; colour from MudFab */
 .minimized-dock {
     position: fixed;