chore: allow using multiple ports for next dev (#43398)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

Trying agents with multiple git worktrees, want the ability to run
multiple instances of dev

## Context

For agent scripts that support git worktrees, you can set STUDIO_PORT to
0 and have the OS assign a port so they don't conflict with each other

.gitignore

@@ -156,4 +156,7 @@ gcloud.json
 keys.json
 
 # Playwright MCP
-.playwright-mcp/*
+.playwright-mcp/*
+
+# Application
+**/.superset/**

apps/studio/package.json

@@ -4,7 +4,7 @@
   "private": true,
   "scripts": {
     "preinstall": "npx only-allow pnpm",
-    "dev": "next dev -p 8082",
+    "dev": "next dev -p ${STUDIO_PORT:-8082}",
     "build": "next build && if [ \"$SKIP_ASSET_UPLOAD\" != \"1\" ]; then ./../../scripts/upload-static-assets.sh; fi",
     "start": "next start -p 8082",
     "lint": "eslint .",