refactor(coach): retire the redundant settings-sheet close-X

The primitive `<SheetContent>` close-X is an absolutely positioned
`opacity-70 rounded-xs` button that clashes with the rest of the
sheet's in-header chrome. Hide it via `showCloseButton={false}` and
render a matching ghost-icon `<SheetClose>` inline in the header
so the close affordance shares the same baseline, ghost variant,
and 44 px tap floor as the coach-drawer header pattern. The
settings-sheet test mock picks up a `SheetClose` passthrough so the
existing skeleton + form assertions keep working.

src/components/insights/coach-panel/__tests__/coach-settings-sheet.test.tsx

@@ -55,6 +55,11 @@ vi.mock("@/components/ui/sheet", () => ({
   SheetDescription: ({ children }: { children: React.ReactNode }) => (
     <p>{children}</p>
   ),
+  // v1.4.27 R3d MB1 — the settings sheet now renders an inline
+  // `<SheetClose>` in the header instead of the primitive's
+  // absolutely-positioned close-X. Mock it as a passthrough so the
+  // existing skeleton + form snapshot assertions keep working.
+  SheetClose: ({ children }: { children: React.ReactNode }) => <>{children}</>,
 }));
 
 import { CoachSettingsSheet } from "../coach-settings-sheet";

src/components/insights/coach-panel/coach-settings-sheet.tsx

@@ -5,8 +5,11 @@ import { useMutation, useQueryClient } from "@tanstack/react-query";
 import { Loader2 } from "lucide-react";
 import { toast } from "sonner";
 
+import { X } from "lucide-react";
+
 import {
   Sheet,
+  SheetClose,
   SheetContent,
   SheetDescription,
   SheetHeader,
@@ -140,16 +143,39 @@ export function CoachSettingsSheet({
     <Sheet open={open} onOpenChange={onOpenChange}>
       <SheetContent
         side="right"
+        // v1.4.27 R3d MB1 — the default `<SheetContent>` close-X is an
+        // absolutely positioned `opacity-70 rounded-xs` button that
+        // clashed with the in-header layout. Match the coach-drawer
+        // pattern instead: hide the primitive's close-X and render a
+        // matching ghost-icon `<SheetClose>` inline in the header so
+        // the close affordance sits on the same baseline as the rest
+        // of the sheet chrome and clears the 44 px tap target.
+        showCloseButton={false}
         data-slot="coach-settings-sheet"
         className="flex h-[100dvh] w-full flex-col gap-0 p-0 sm:max-w-[420px]"
       >
-        <SheetHeader className="border-border/70 border-b p-4 pr-12">
-          <SheetTitle className="text-sm font-semibold">
-            {t("insights.coach.settingsTitle")}
-          </SheetTitle>
-          <SheetDescription className="text-muted-foreground text-xs">
-            {t("insights.coach.settingsDescription")}
-          </SheetDescription>
+        <SheetHeader className="border-border/70 flex-row items-start gap-2 border-b p-4">
+          <div className="min-w-0 flex-1">
+            <SheetTitle className="text-sm font-semibold">
+              {t("insights.coach.settingsTitle")}
+            </SheetTitle>
+            <SheetDescription className="text-muted-foreground text-xs">
+              {t("insights.coach.settingsDescription")}
+            </SheetDescription>
+          </div>
+          <SheetClose asChild>
+            <Button
+              type="button"
+              variant="ghost"
+              size="icon"
+              data-slot="coach-settings-sheet-close"
+              aria-label={t("common.close")}
+              title={t("common.close")}
+              className="text-muted-foreground hover:text-foreground -mt-1 shrink-0"
+            >
+              <X className="size-4" aria-hidden="true" />
+            </Button>
+          </SheetClose>
         </SheetHeader>
 
         {isLoading ? (