Settings-dialog round 1 staging repair: the provider-rewiring files

Round 1 (27d4f33) listed sidebar.tsx, keyboard-shortcuts.tsx,
app/settings/page.tsx and the globals.css keyframes in its message but
they were never staged. This commits exactly that content: the sidebar
Settings row as a button calling the dialog provider, the mod+, chord
opening the dialog, /settings redirecting to /chat/new, and the
settings-pop keyframes (reduced-motion aware). No new changes —
catch-up staging only. (next-env.d.ts churn left untracked-in-commit as
dev-server noise.)

app/globals.css

@@ -389,6 +389,30 @@ body {
 	}
 }
 
+/* Settings dialog pop (settings-app wave, 2026-09-20): a short fade +
+   2% settle-scale — understated by design, the app's motion taste
+   (200ms sidebar, 150ms here); honors reduced-motion by appearing. */
+@keyframes settings-pop {
+	from {
+		opacity: 0;
+		scale: 0.98;
+	}
+	to {
+		opacity: 1;
+		scale: 1;
+	}
+}
+
+.settings-dialog-pop {
+	animation: settings-pop 150ms ease-out;
+}
+
+@media (prefers-reduced-motion: reduce) {
+	.settings-dialog-pop {
+		animation: none;
+	}
+}
+
 /* ─────────────────────────────────────────────────────────────────────────
    Electron merged chrome (owner, 2026-09-17). The system title bar is
    hidden (titleBarStyle: "hiddenInset" in electron/main.cjs); the app's