Port conflict handling is not user-friendly (should fallback or guide user)

# ActivityWatch Port Conflict Handling

## 📄 Description

When port **5600** is already in use, ActivityWatch fails to start and shows:

> Address already in use
> Port 5600 is in use by another program. Either identify and stop that program, or start the server with a different port.

This creates confusion because:

* The user cannot tell what is using the port
* No automatic fallback is attempted
* No guidance is provided

## 💡 Suggested Improvements

* Detect if port is already in use
* Either:

* Automatically select the next available port (e.g. 5601, 5602)
* **OR** clearly show:

* Which process is using the port
* How to resolve it

### Optional Enhancements

* Allow configurable default port

## 🎯 Why? very important to the end user and is a part of UX design

## ⚔️ When Does This Happen?

### ✅ Case 1: ActivityWatch already running

Most common case.

You tried to start it again → conflict occurs.

### ⚠️ Case 2: Another application using the port

Rare, but possible.

Any application can bind to any free port.

### 🔁 Case 3: Previous instance didn’t shut down properly

A leftover (zombie) process is still holding the port.

# 🙋 Contribution

I’d be interested in working on this if the approach aligns with the project direction.