Support HTMLElement in useReward for direct template ref usage

[Copilot]

Enables passing HTMLElement or Vue refs directly to useReward, eliminating the need for string IDs when using Vue 3.5's useTemplateRef.

Changes

Type signature update

• useReward now accepts MaybeRefOrGetter<string | HTMLElement> instead of just string
• Handles refs, getters, and plain values reactively via toValue()

Runtime validation

• getContainerById validates HTMLElement instances with instanceof check
• Returns HTMLElement | null for proper null handling

Type safety

• Added explicit types: RewardType, RewardConfig
• Proper config typing for confetti/emoji/balloons variants

Usage

<script setup lang="ts">
import { ref } from 'vue'
import { useReward } from 'vue-rewards'

// New: pass template ref directly
const containerRef = ref<HTMLElement | null>(null);
const { reward } = useReward(containerRef, 'balloons');

// Still works: traditional string ID
const { reward: confetti } = useReward('my-id', 'confetti');
</script>

<template>
  <button @click="reward">
    <span ref="containerRef"></span>
    🎈 Balloons
  </button>
</template>

Fully backward compatible. Existing string ID usage unchanged.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Feature: Allow string | HTMLDivElement in constructor optionally</issue_title>
<issue_description>This will make the composable dynamic instead of static id.
It's also more ergonomic to work with Vue 3.5 with useTemplateRef.
Thanks!

<script lang="ts" setup>
  const containerRef = useTemplateRef('container')
  useReward(containerRef.value)
</script>

<template>
  <div ref="container">
  </div>
</template>
```</issue_description>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Feature: Allow string | HTMLDivElement in constructor optionally #8

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[HamadaFMahdi]

@@andrewspy

[andrewspy]

I tried the branch by specifying the following in package.json, but somehow VSCode can't recognise vue-rewards with the message below.

package.json

"vue-rewards": "github:HamadaFMahdi/vue-rewards#copilot/add-string-html-element-support"

Typescript error:

Cannot find module 'vue-rewards' or its corresponding type declarations.