Add Inertia Prefetch support

[Copilot]

This PR adds comprehensive support for Inertia Prefetch functionality to the vuetify-inertia-link plugin, following Inertia.js's exact implementation patterns and behavior.

What's New

The plugin now supports Inertia-style prefetching with proper defaults and multiple prefetch modes:

• Disabled by Default: Prefetching is disabled by default, matching Inertia.js behavior
• Multiple Prefetch Modes: Support for 'hover', 'click', and 'mount' modes exactly like Inertia
• Proper Timing: 75ms hover delay matching Inertia's implementation
• Smart Caching: 30-second default cache duration with configurable cacheFor prop
• Current Page Detection: Automatically avoids prefetching the current page

Usage

By default, links do not prefetch (matching Inertia's behavior):

<!-- No prefetching by default -->
<v-btn :to="route('dashboard')">Dashboard</v-btn>

Enable prefetching explicitly:

<!-- Enable hover prefetching -->
<v-btn :to="route('dashboard')" :prefetch="true">Dashboard</v-btn>

<!-- Specific prefetch modes -->
<v-btn :to="route('dashboard')" prefetch="hover">Hover prefetch</v-btn>
<v-btn :to="route('dashboard')" prefetch="click">Click prefetch</v-btn>
<v-btn :to="route('dashboard')" prefetch="mount">Mount prefetch</v-btn>

<!-- Multiple modes -->
<v-btn :to="route('dashboard')" :prefetch="['hover', 'click']">Multiple modes</v-btn>

<!-- Custom cache duration -->
<v-btn :to="route('dashboard')" :prefetch="true" :cache-for="60000">60s cache</v-btn>

Implementation Details

The implementation closely follows Inertia's Vue3 link component:

1. Prefetch Modes:

   • hover: Prefetches after 75ms hover delay (Inertia's exact timing)
   • click: Prefetches on mousedown, navigates on mouseup for instant feel
   • mount: Prefetches immediately when component renders

2. Event Handling: Different event handlers for each prefetch mode, matching Inertia's patterns

3. Caching: Uses Inertia's router.prefetch() with proper cacheFor options

4. Smart Defaults: When prefetch={true}, defaults to 'hover' mode like Inertia

Backward Compatibility

This is a breaking change in default behavior but maintains API compatibility:

• Existing code without prefetch props continues to work (no prefetching)
• Previous implementations expecting prefetch-by-default need explicit prefetch={true}

Fixes #2.

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[gigerIT]

@copilot analyze the docs https://inertiajs.com/prefetching.md and implement everything like Inertia did (e.g. prefetch=false as default).

Analyze their source https://github.com/inertiajs/inertia to figure out how prefetch is implemented and how you can adapt to it from this plugin.

[Copilot]

@copilot analyze the docs https://inertiajs.com/prefetching.md and implement everything like Inertia did (e.g. prefetch=false as default).

Analyze their source https://github.com/inertiajs/inertia to...

I've analyzed the Inertia.js source code and completely reimplemented the prefetching to match their exact behavior. Key changes made in commit 892b47f:

Fixed Default Behavior: Changed prefetch default from true to false to match Inertia.js
Proper Prefetch Modes: Implemented 'hover' (75ms timeout), 'click', and 'mount' modes exactly like Inertia
Correct Timing: Updated timeout from 100ms to 75ms to match Inertia's implementation
Caching Support: Added cacheFor prop with 30-second default matching Inertia's behavior
Event Handling: Restructured event handlers to match Inertia's patterns for different prefetch modes

The implementation now follows Inertia's source code patterns precisely, with prefetch disabled by default and explicit opt-in behavior.