Component for displaying character count and input limits in form fields with customizable formatting templates.

FieldCounter provides visual feedback about the number of entered characters, automatically formats display depending on the presence of a maximum limit, and supports flexible customization through templates with placeholders. The component integrates with text fields and text areas, providing users with information about restrictions and remaining input space.

**Key features:**

- Display current number of entered characters
- Automatic maximum limit display when present
- Flexible formatting templates with [c] and [m] placeholders
- Automatic format detection (50 / 100 or just 50)
- Support for string and numeric counter and maxlength values
- Smart visibility management via counterShow property
- Compact display for space efficiency

**Common use cases:**

- Text fields with character count limits
- Multi-line text areas (textarea) for descriptions
- Comment input fields with limits
- Forms with minimum/maximum length requirements
- SMS editors with character counting

```html
<script setup>
import { ref } from 'vue'

const message = ref('')
const bio = ref('')
</script>

<template>
  <!-- Counter only without limit -->
  <FieldCounter :counter="message.length" />

  <!-- Counter with maximum limit (format: 50 / 200) -->
  <FieldCounter
    :counter="message.length"
    :maxlength="200"
  />

  <!-- Custom display template -->
  <FieldCounter
    :counter="bio.length"
    :maxlength="500"
    template="Characters: [c] of [m]"
  />

  <!-- HTML in template for styling -->
  <FieldCounter
    :counter="message.length"
    :maxlength="160"
    template="<b>[c]</b> / [m] characters"
  />

  <!-- Conditional display via counterShow -->
  <FieldCounter
    :counter="message.length"
    :maxlength="100"
    :counterShow="message.length > 0"
