Update app.js

[r0path]

Display name of registered user.

[zeropath-ai]

❌ Possible security or compliance issues detected. Reviewed everything up to a7449ce.

Security Overview

• 🔎 Scanned files: 1 changed file(s)

Detected Code Changes

Change Type	Relevant files
Enhancement	► app.js     Update user welcome message to include name

The following issues were found:

• Cross Site Scripting (XSS): No patch for this bug could be generated. Here is a description and location:
  Location: server.js:70:70
  Description: Potential XSS vulnerability due to unescaped user input being injected into HTML output.
  Link to UI: https://zeropath.com/app/issues/66ce5e74-5bcb-46aa-a3f4-34c1572026a8

Reply to this PR with @zeropath-ai followed by a description of what change you want and we'll auto-submit a change to this PR to implement it.