feat(a11y): touch-visible card controls + modal focus trap/restore (E4 S6)

UX-7 — hover-only card actions were `opacity-0 group-hover:opacity-100`: fine on
a mouse, but invisible AND still tappable on a touch device (no hover). New
`.reveal` primitive (index.css) gates the hide on `@media (hover: hover)`, so a
touch device keeps the control visible; its partner `.reveal-idle` is the idle
badge a control replaces (watched/in-progress pill under the watched-toggle),
faded on hover and dropped on touch so the two don't collide at the same corner.
Migrated the true controls — feed card action toolbar (VideoCard), Plex poster
card watched-toggle/info/add across all card variants + their swap badges
(plexCards), message pop-out (Messages), edit-interval pencil (Scheduler), and
saved-view star/rename/delete (SavedViewsWidget). Pure play-scrim overlays (the
whole card is the tap target) stay hover-only by design.

FE-9 — Modal.tsx had aria-modal but no focus management. Adds: a Tab/Shift+Tab
focus trap (topmost layer only, wraps at the edges and pulls escaped focus back);
initial focus into the dialog unless an autoFocus child already placed it; focus
restore to the trigger on close (captured in a useState initializer during render,
before commit runs autoFocus and moves activeElement inside); and aria-labelledby
wiring the dialog to its title.

Gate green (tsc, knip, lint 0-err, 247 vitest). Self-E2E (localdev): FE-9 trap
both directions + pull-back + Escape-restore-to-trigger + aria-labelledby verified;
UX-7 feed toolbar opacity 0 on desktop / 1 under mobile (hover:none) emulation,
Plex reveal buttons opacity 1 + reveal-idle badges display:none on touch.

frontend/src/components/Modal.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef, type ReactNode } from "react";
+import { useEffect, useId, useRef, useState, type ReactNode } from "react";
 import { createPortal } from "react-dom";
 import { useTranslation } from "react-i18next";
 import { X } from "lucide-react";
@@ -6,6 +6,14 @@ import { useBackToClose } from "../lib/history";
 import { pushLayer, removeLayer, isTopmost } from "../lib/layerStack";
 import { useFullscreenElement } from "../lib/fullscreen";
 
+// Tabbable elements inside the dialog, in DOM order. `:not([tabindex="-1"])` drops programmatically
+// focusable-only nodes; the visibility filter (offsetParent) drops display:none ones (e.g. a
+// collapsed disclosure) so the trap never lands focus on something the user can't see.
+const FOCUSABLE =
+  'a[href], button:not([disabled]), textarea:not([disabled]), input:not([disabled]), select:not([disabled]), [tabindex]:not([tabindex="-1"])';
+const focusablesIn = (root: HTMLElement): HTMLElement[] =>
+  [...root.querySelectorAll<HTMLElement>(FOCUSABLE)].filter((el) => el.offsetParent !== null);
+
 // Small centered modal shell: backdrop + ESC + scroll-lock close. Each open modal is a layer in the
 // shared `layerStack` so ESC only closes the topmost one — e.g. an error dialog over the tag editor
 // dismisses just the error and returns to the editor underneath, and a player below defers to it
@@ -27,6 +35,13 @@ export default function Modal({
   // Browser/mouse Back closes the topmost modal instead of navigating away.
   useBackToClose(onClose);
   const fsRoot = useFullscreenElement();
+  const panelRef = useRef<HTMLDivElement>(null);
+  const titleId = useId();
+  // Capture the trigger to restore focus to, during THIS render — i.e. before commit runs the
+  // dialog's autoFocus (or our own initial-focus) and moves activeElement into the dialog. Reading
+  // it later (in the effect) would capture a now-inside element that unmounts on close, stranding
+  // focus on <body>. useState initializer runs exactly once, on first render.
+  const [restoreTo] = useState(() => document.activeElement as HTMLElement | null);
 
   // Backdrop-click close must only fire when the press STARTED on the backdrop too. Otherwise a
   // drag that begins inside the dialog (e.g. selecting text in an input) and is released out on
@@ -39,20 +54,55 @@ export default function Modal({
   useEffect(() => {
     const id = pushLayer();
     const onKey = (e: KeyboardEvent) => {
-      if (e.key === "Escape" && isTopmost(id)) {
+      if (!isTopmost(id)) return;
+      if (e.key === "Escape") {
         e.stopPropagation();
         onCloseRef.current();
+        return;
+      }
+      // Focus trap: keep Tab / Shift+Tab cycling inside the dialog instead of reaching the inert
+      // page behind the backdrop. Only the topmost modal traps (a nested one defers to its child).
+      if (e.key === "Tab") {
+        const panel = panelRef.current;
+        if (!panel) return;
+        const items = focusablesIn(panel);
+        const first = items[0];
+        const last = items[items.length - 1];
+        if (!first || !last) {
+          e.preventDefault();
+          return;
+        }
+        const active = document.activeElement;
+        if (!panel.contains(active)) {
+          // Focus escaped the dialog (or sits on the panel itself) — pull it back to an edge.
+          e.preventDefault();
+          (e.shiftKey ? last : first).focus();
+        } else if (e.shiftKey && active === first) {
+          e.preventDefault();
+          last.focus();
+        } else if (!e.shiftKey && active === last) {
+          e.preventDefault();
+          first.focus();
+        }
       }
     };
     window.addEventListener("keydown", onKey);
     const prev = document.body.style.overflow;
     document.body.style.overflow = "hidden";
+    // Initial focus: unless an autoFocus child already placed it inside (e.g. a rename input), move
+    // focus to the first control so the dialog opens focused, not stranded on the background.
+    const panel = panelRef.current;
+    if (panel && !panel.contains(document.activeElement)) {
+      (focusablesIn(panel)[0] ?? panel).focus();
+    }
     return () => {
       window.removeEventListener("keydown", onKey);
       removeLayer(id);
       document.body.style.overflow = prev;
+      // Restore focus to the trigger, if it's still in the document and focusable.
+      if (restoreTo && restoreTo.isConnected) restoreTo.focus();
     };
-  }, []);
+  }, [restoreTo]);
 
   return createPortal(
     <div
@@ -65,10 +115,17 @@ export default function Modal({
       }}
       role="dialog"
       aria-modal="true"
+      aria-labelledby={titleId}
     >
-      <div className={`glass relative w-full ${maxWidth} max-h-full overflow-y-auto rounded-2xl`}>
+      <div
+        ref={panelRef}
+        tabIndex={-1}
+        className={`glass relative w-full ${maxWidth} max-h-full overflow-y-auto rounded-2xl outline-none`}
+      >
         <div className="flex items-start justify-between gap-3 p-5 pb-3">
-          <h2 className="text-lg font-semibold leading-snug">{title}</h2>
+          <h2 id={titleId} className="text-lg font-semibold leading-snug">
+            {title}
+          </h2>
           <button
             onClick={onClose}
             title={t("common.close")}