Add telnet:// URI scheme support for one-click MUD connections

Summary

This PR implements telnet:// URI scheme support, allowing users to connect to MUD servers with a single click. This addresses the long-standing feature request in issue #689 from 2013.

What this PR does

• Adds telnet:// URI parsing and handling in command-line arguments
• Implements intelligent profile matching - reuses existing profiles when available
• Auto-creates new profiles when connecting to unknown servers
• Provides cross-platform OS integration for browser and system-wide telnet:// link support
• Handles multi-instance coordination - routes URIs to existing Mudlet instances

How it works

User Experience

1. User clicks a telnet://server.com:port link in browser or application
2. Mudlet automatically opens (or receives the URI if already running)
3. If a matching profile exists → loads the most recently used one
4. If no profile exists → creates new profile with server details and connects
5. User is immediately connected to the MUD server

Key Features

• URI Format Support: telnet://host[:port] with port defaulting to 23
• Profile Matching: Host + port based matching with existing profiles
• Smart Naming: Profiles named as “hostname” or “hostname:port” for non-standard ports
• Collision Handling: Automatic numbering for duplicate profile names
• Multi-instance: Routes to existing Mudlet instance when available

Testing

The implementation has been tested with:

• Various telnet:// URI formats (telnet://server.com, telnet://server.com:4000)
• Profile creation and reuse scenarios
• Multi-instance coordination
• Real MUD server connections (e.g., telnet://aardmud.org:4000)

Test Commands

# Test basic connection with port
./mudlet "telnet://aardmud.org:4000"

# Test default port (23)
./mudlet "telnet://batmud.bat.org"

# Test profile reuse (run twice)
./mudlet "telnet://testserver.example.com:1234"

https://github.com/user-attachments/assets/981cb718-5587-4fcb-a210-c182430b79a4

Players clicking these links will have Mudlet automatically open and connect.

Closes

Fixes #689

/claim #689

Type of change

• New feature (non-breaking change which adds functionality)
• Enhancement to existing feature
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)