fvtt-version-compat

# Foundry VTT Version Compatibility (V12/V13/V15+)

Use compatibility wrappers to avoid deprecation warnings when APIs move from globals to namespaces across Foundry versions.

## When to Use This Skill

Invoke this skill when:

### ✅ Use Compat Wrappers For:

- **Importing Foundry classes** - ActorSheet, ItemSheet, TextEditor
- **Registering sheets** - Actor sheets, item sheets, document sheets
- **Loading templates** - Handlebars template loading
- **Enriching HTML** - TextEditor.enrichHTML for journal content
- **Generating IDs** - randomID() for unique identifiers
- **Any Foundry API** - That has moved or will move to namespaces

### ❌ Don't Use Compat Wrappers For:

- **Stable globals** - `game`, `ui`, `CONFIG`, `Hooks`
- **Project-specific code** - Your own classes and functions
- **One-off migrations** - If only targeting a single Foundry version
- **Styling/layout** - CSS and templates (not API drift)

## The Problem: API Migration Across Versions

### What Changed Across Foundry Versions

**Foundry V11/V12 (Legacy):**
```javascript
// APIs available as globals
ActorSheet
ItemSheet
TextEditor.enrichHTML()
loadTemplates()
renderTemplate()
randomID()
Actors.registerSheet()
```

**Foundry V13+ (Namespaced):**
```javascript
// APIs moved to namespaces
foundry.appv1.sheets.ActorSheet
foundry.appv1.sheets.ItemSheet
foundry.applications.ux.TextEditor.implementation.enrichHTML()
foundry.applications.handlebars.loadTemplates()
foundry.applications.handlebars.renderTemplate()
foundry.utils.randomID()
foundry.applications.api.DocumentSheetConfig.registerSheet()
```

**Foundry V15+ (Legacy Removed):**
```
Globals will be REMOVED entirely
  ↓
Direct global access will break
  ↓
Must use namespaced APIs only
```

### Why This Breaks Code

```javascript
// ❌ This worked in V11/V12, will BREAK in V15+
import { ActorSheet } from "somewhere";  // No longer a global!

class MySheet extends ActorSheet {
  // ...
}

// ❌ This throws deprecation warnings in V13
TextEditor.enrichH