Rename project to voice-dev

- Rename all packages from @realtime-voice/* to @voice-dev/*
- Update root package.json name and description
- Update README with new branding and remove monorepo terminology
- Rename GitHub repo to voice-dev
- Remove Vercel link to prepare for fresh deployment

packages/mcp-server/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "@realtime-voice/mcp-server",
+  "name": "@voice-dev/mcp-server",
   "version": "0.3.0",
   "description": "MCP Server for interfacing with tmux sessions",
   "type": "module",