Add a migration skill

Author: daniloc

llm-prompts/migrate-amplitude/1.0-begin.md

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+---
+title: Amplitude Migration - Begin
+description: Scan the project for Amplitude SDK usage and create a migration plan
+---
+
+You are migrating this project from Amplitude Analytics to PostHog.
+
+## Step 1: Detect Amplitude Installation
+
+Check `package.json` for any of these Amplitude packages:
+- `@amplitude/analytics-browser`
+- `@amplitude/analytics-node`
+- `@amplitude/analytics-react-native`
+- `amplitude-js`
+
+Note which packages are installed and their versions.
+
+## Step 2: Scan for Amplitude Code
+
+Search the codebase for files containing Amplitude usage:
+
+1. **Import statements** - Look for:
+   - `from '@amplitude/analytics-browser'`
+   - `from 'amplitude-js'`
+   - `from '@amplitude/analytics-node'`
+   - `from './ampli'` (generated Amplitude SDK)
+
+2. **Initialization code** - Look for:
+   - `init('AMPLITUDE_API_KEY')`
+   - `amplitude.getInstance().init()`
+   - `ampli.load()`
+
+3. **Tracking calls** - Look for:
+   - `track()`, `logEvent()`
+   - `identify()`, `setUserId()`
+   - `setGroup()`, `groupIdentify()`
+   - `revenue()`, `Revenue`
+   - Ampli type-safe methods like `ampli.buttonClicked()`
+
+4. **Configuration files** - Check for Amplitude environment variables:
+   - `AMPLITUDE_API_KEY`
+   - `REACT_APP_AMPLITUDE_API_KEY`
+   - `NEXT_PUBLIC_AMPLITUDE_API_KEY`
+   - `VITE_AMPLITUDE_API_KEY`
+
+## Step 3: Create Migration Plan
+
+Create a file `.posthog-migration.json` at the project root with:
+
+```json
+{
+  "sourceProvider": "amplitude",
+  "detectedPackages": ["@amplitude/analytics-browser"],
+  "filesToMigrate": [
+    {
+      "path": "src/index.tsx",
+      "patterns": ["initialization", "provider-setup"]
+    },
+    {
+      "path": "src/components/Button.tsx",
+      "patterns": ["event-tracking"]
+    }
+  ],
+  "hasAmpliSdk": false,
+  "ampliDirectory": null,
+  "environmentVariables": {
+    "remove": ["AMPLITUDE_API_KEY"],
+    "add": ["POSTHOG_KEY", "POSTHOG_HOST"]
+  }
+}
+```
+
+## Step 4: Determine PostHog Package
+
+Map Amplitude packages to PostHog equivalents:
+- `@amplitude/analytics-browser` → `posthog-js`
+- `amplitude-js` → `posthog-js`
+- `@amplitude/analytics-node` → `posthog-node`
+
+## Status
+
+Report these status updates as you work:
+
+- [STATUS] Checking for Amplitude installation
+- [STATUS] Scanning for Amplitude usage patterns
+- [STATUS] Found X files with Amplitude code
+- [STATUS] Creating migration plan