Fix per-frame render jank from toggle-input-card focus (#4300)

## Problem

Enabling **Starting Gold** (or **Game Timer** / **Gold Multiplier**) in
the single-player / host-lobby modal made the page spend several ms of
"Render" time **every frame** — for as long as the toggle stayed
enabled. Disabling the option made it stop.

## Root cause

Each `toggle-input-card`, on enable, auto-focused and selected its
number input so you could type immediately:

```ts
input.focus();
input.select();
```

A focused/selected editable inside the modal keeps the browser doing
layout/paint work every frame for as long as it stays focused. It
reproduces for any of the toggle-input cards because they all auto-focus
on enable, which is why Starting Gold, Game Timer, and Gold Multiplier
all triggered it.

> **Note on the earlier revision of this PR:** the first attempt passed
`{ preventScroll: true }` to `focus()`, on the theory that
scroll-into-view was the cause. It successfully stopped the scroll
(verified: modal scroll container `scrollTop 0 → 0`), but the per-frame
render cost remained. That ruled out scroll-into-view and proved the
focused editable itself — not the scroll — was the trigger.

## Fix

Remove the auto-focus entirely. Enabling a toggle no longer focuses its
number input, and the per-frame render cost is gone.

## Trade-off

You no longer get type-to-replace on enable — click the field before
typing the value. Worth it to eliminate the per-frame render.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/client/components/ToggleInputCard.ts

@@ -1,4 +1,4 @@
-import { LitElement, PropertyValues, html, nothing } from "lit";
+import { LitElement, html, nothing } from "lit";
 import { customElement, property } from "lit/decorators.js";
 import { translateText } from "../Utils";
 import { CARD_LABEL_CLASS, INPUT_CLASS, cardClass } from "./InputCardStyles";
@@ -28,19 +28,6 @@ export class ToggleInputCard extends LitElement {
   createRenderRoot() {
     return this;
   }
-
-  protected updated(changedProperties: PropertyValues<this>) {
-    if (!changedProperties.has("checked")) return;
-    const previousChecked = changedProperties.get("checked");
-    if (previousChecked === false && this.checked) {
-      const input = this.querySelector("input");
-      if (input) {
-        input.focus();
-        input.select();
-      }
-    }
-  }
-
   private toOptionalNumber(
     value: number | string | undefined,
   ): number | undefined {