fix(ui): right rail tabs: review fixes, launcher in the strip, strip never scrolls on common windows

Review fixes P1.1-P2.7: a panel hidden at mount gets its tab when revealed; any live opening of a rail panel makes it the owner, restores do not; a short lane scrolls the strip with a thin scrollbar and brings a newly opened tab into view once; the join and the panel cover stay inside the lane and the fillet shrinks to the room left; a share link carries an owner-collapsed peer as collapsed so the recipient opens the sender's panel; border-box on phones; the strip's column folds into the panel width at 721-760px; the focus ring draws inside the tab.

The compact Radio launcher moves from Context's header into a tool slot under the tabs on desktop (back into the header for the phone sheet) and always toggles the compact player, also while Context is open; the player's Details button leads to the Radio section. The jump-to-section role, its two labels and the #804 closings of the player on Context expansion and rail layout passes are gone with it.

The rail panels' own collapse arrows are hidden on desktop: the tab opens and closes a panel, Escape inside closes it and returns focus to the tab.

The tabs are denser and the rail climbs toward the HUD corner above its left-rail baseline when the strip's column is taller than the lane, so the strip no longer scrolls on windows down to about 680px tall; the measuring pass keeps the strip's scroll offset. scripts/qa-radio.mjs expectations follow the launcher's new role.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

src/ui/radioControls.js

@@ -109,94 +109,12 @@ export class RadioControls {
     return true;
   }
 
-  /**
-   * Bring the embedded Radio section into the expanded Context scroller.
-   * This never changes Radio power, playback, selection, or Context mode.
-   * @param {{focusTarget?: HTMLElement|null}} [options]
-   * @returns {Promise<boolean>} Whether the internal scroller moved.
-   */
-  async _revealRadioPanelInsideContext({ focusTarget = null } = {}) {
-    const contextPanel = document.getElementById('global-context-panel');
-    const scroller =
-      (document.documentElement?.dataset.uiTheme === 'cyber' &&
-        contextPanel?.querySelector('.cyber-panel-body')) ||
-      contextPanel?.querySelector('.global-context-panel-inner');
-    if (
-      !contextPanel ||
-      contextPanel.classList.contains('collapsed') ||
-      !scroller ||
-      !this._radioPanel ||
-      this._radioPanel.classList.contains('collapsed')
-    )
-      return false;
-
-    await new Promise((resolve) =>
-      requestAnimationFrame(() => requestAnimationFrame(resolve)),
-    );
-    if (
-      this.destroyed ||
-      contextPanel.classList.contains('collapsed') ||
-      this._radioPanel.classList.contains('collapsed')
-    )
-      return false;
-
-    const viewport = scroller.getBoundingClientRect();
-    const radioRect = this._radioPanel.getBoundingClientRect();
-    const desired = scroller.scrollTop + radioRect.top - viewport.top - 10;
-    const next = Math.min(
-      Math.max(0, scroller.scrollHeight - scroller.clientHeight),
-      Math.max(0, desired),
-    );
-    const moved = Math.abs(next - scroller.scrollTop) >= 1;
-    if (moved) {
-      const reducedMotion = window.matchMedia?.(
-        '(prefers-reduced-motion: reduce)',
-      )?.matches;
-      scroller.scrollTo({
-        top: next,
-        behavior: reducedMotion ? 'auto' : 'smooth',
-      });
-    }
-    focusTarget?.focus?.({ preventScroll: true });
-    return moved;
-  }
-
-  /** Keep the launcher truthful for the active theme and Context route. */
+  /** Keep the launcher's ARIA state matched to the compact player. */
   _syncContextRadioLauncherState() {
     if (this.destroyed || !this._contextRadioToggleBtn) return;
-    const contextPanel = globalThis.document?.getElementById(
-      'global-context-panel',
-    );
-    const contextExpanded = Boolean(
-      contextPanel && !contextPanel.classList.contains('collapsed'),
-    );
-    if (contextExpanded) {
-      const radioExpanded = Boolean(
-        this._radioPanel && !this._radioPanel.classList.contains('collapsed'),
-      );
-      this._contextRadioToggleBtn.setAttribute('aria-controls', 'radio-panel');
-      this._contextRadioToggleBtn.setAttribute(
-        'aria-expanded',
-        String(radioExpanded),
-      );
-      const label = t(
-        radioExpanded
-          ? msg('Go to expanded Radio section')
-          : msg('Expand Radio section in Context'),
-      );
-      this._contextRadioToggleBtn.setAttribute('aria-label', label);
-      this._contextRadioToggleBtn.title = label;
-      return;
-    }
-    // This launcher toggles the compact player even when the detailed panel
-    // is open elsewhere. Its ARIA state must describe that same disclosure.
     const compactOpen = Boolean(
       this._contextRadioDock?.classList.contains('disclosure-open'),
     );
-    this._contextRadioToggleBtn.setAttribute(
-      'aria-controls',
-      'context-radio-mini',
-    );
     this._contextRadioToggleBtn.setAttribute(
       'aria-expanded',
       String(compactOpen),