fix(e10): review round 1 — the boundary that did not bind, and 14 more

The epic-end review found 32 verified issues. This is the first fix round:
the three highs, the user-facing mediums, and the tests that were passing
for the wrong reason. Docs and the remaining low-severity tail are next.

The boundary rule was the worst of them. Both `no-restricted-imports`
regexes were written in plain "..." literals, where `\.` is an unknown
escape that collapses to the any-char `.` — so the rule read like a
boundary and matched far less than one. `../../lib/api` (the barrel every
feature component imports) and `../../components/Feed` (the same file
`../Feed` names) both sailed through a green gate. String.raw, a third
pattern for the second spelling, and a vitest over ESLint.lintText so a
rule that silently matches nothing can never look like a clean codebase
again.

closeThenNavigate waited for exactly one reclaim popstate. With a second
Back-closable layer still mounted — a palette opened over the player —
the navigation unmounted that layer too, and its reconcile backed over
the entry the navigation had just pushed: "go to Channels" closed the
player and landed on the feed. It now waits for the LAST programmatic
back, then adopts the entries the navigation buried, and falls back after
250ms rather than hanging if no popstate is ever coming.

The rail's inline rename died on arrival. With no domReference, floating-
ui's returnFocus falls through to a module-global stack and restores some
unrelated element from an earlier popover — blurring the field into its
own commit-and-close, from the second popover of a session onward. The
context menu now owns the restore: back to the row, but only if the row
is still there and nothing else has claimed focus.

Also:
- Backspace under the cheat sheet stopped Plex playback and dropped to
  the grid; `back` now defers to any layer above, like `escape` beside it.
- A move invalidated only the source list, so the target kept serving
  pre-move contents for 30s while the rail already counted N+1.
- Every move error a user can reach is a 404, which `req` leaves to the
  caller — so the row snapped back in silence and the shipped moveErrors
  strings were unreachable.
- swallowClick armed on long-press but was disarmed only by the click it
  was armed for; any press that produced no click ate the next tap on the
  whole list.
- The context menu stayed parked over whatever row scrolled under it.
- overflow-clip on the chip lanes ate the focus ring's top and bottom.
- "Why is this off" rode on disabled rows, which show no tooltip and take
  no focus: a new `inert` item keeps the reason readable.
- Shift+F10 was advertised app-wide but wired only on Playlists; it has
  its own scope now, and useContextMenu matches through the shared parser
  instead of its own literals.
- Mod+K could not close the palette, `h` machine-gunned on auto-repeat,
  and both were bound above the branch that mounts their overlays.
- Palette options were in the tab order under aria-activedescendant, and
  a scroll-synthesised mousemove stole the keyboard selection.
- The OSD live region was created together with its own text.
- Ending a rename stranded focus on <body>.
- The Button variants' hover halves are `enabled:` — the one migrated
  site that had guarded its own lost the guard on the way in.
- HU builtinLocked named the list "Watch later" in a Hungarian sentence.

Tests: the chip-lane contract counted per FILE, so a second hand-rolled
lane in an already-compliant file was invisible; the closeThenNavigate
ordering test only passed on a popstate left behind by its neighbours and
failed alone, so it moved to its own file.

frontend/src/components/ui/CommandPalette.tsx

@@ -64,6 +64,8 @@ export default function CommandPalette({
   // Ref on the highlighted row rather than a selector lookup: item ids come from domain data
   // (playlist names, channel handles) and would need escaping to be safe in a query string.
   const activeRef = useRef<HTMLButtonElement | null>(null);
+  // Last pointer position, so a mousemove the BROWSER synthesised can be told from one the user made.
+  const lastPointer = useRef<{ x: number; y: number } | null>(null);
 
   // A fresh open starts from a blank field: the palette is for "take me somewhere", and a leftover
   // query from last time hides everything you might want now.
@@ -158,8 +160,22 @@ export default function CommandPalette({
                   role="option"
                   aria-selected={item.id === activeId}
                   type="button"
+                  // The combobox input owns the tab stop; the arrows move a VIRTUAL selection over
+                  // these rows. Leaving them tabbable put DOM focus on a row while
+                  // aria-activedescendant named a different one — two competing "current" options —
+                  // and made Tab walk every result (E10 review round 1).
+                  tabIndex={-1}
                   onClick={() => choose(item)}
-                  onMouseMove={() => setActive(flat.indexOf(item))}
+                  onMouseMove={(e) => {
+                    // Only a pointer that actually MOVED may take the selection. After the arrow keys
+                    // scroll a row past the fold, Blink re-dispatches a mousemove at the unchanged
+                    // cursor position to refresh hover — which handed the highlight straight back to
+                    // whatever row slid under a resting cursor (E10 review round 1).
+                    const prev = lastPointer.current;
+                    lastPointer.current = { x: e.clientX, y: e.clientY };
+                    if (prev && prev.x === e.clientX && prev.y === e.clientY) return;
+                    setActive(flat.indexOf(item));
+                  }}
                   className={`flex w-full items-center gap-2 rounded-lg px-2 py-1.5 text-left text-sm ${
                     item.id === activeId ? "bg-card text-fg" : "text-muted hover:text-fg"
                   }`}