feat: add port_info() default method to SerialPort trait

[KaustubhOG]

Closes #276

Problem

There is currently no way to retrieve SerialPortInfo from an opendyn SerialPort without calling available_ports() manually and searching by name.

Solution

Add a default port_info() method to the SerialPort trait. The implementation calls self.name(), enumerates available ports, and returns the matching SerialPortInfo entry.

Since it is a default method, all existing implementors (TTYPort,COMPort, and the &mut T blanket impl) get it for free with no changes required on their end.

Returns Err if:

• the port has no name (e.g. virtual/pseudo-terminal ports)
• available_ports() fails
• no matching port is found

Notes

• All existing tests pass
• Platform-specific types can override this method in the future
  if a faster implementation is needed (e.g. caching info at open time)

[KaustubhOG]

Should this target the playground-5.0 branch instead of main, given that it touches the SerialPort trait? i read some old pr where you listed it specific point

[sirhcel]

Thank you for starting this draft PR @KaustubhOG! Please see my comment #276 (comment) in the original issue.

Regarding this PR: Enumerating all ports for identifying the details of a single one looks somewhat like a brute force approach. Sure, this is what we could do with just the current public API. Did you have a look into how information for a certain port could be fetched with the enumeration mechanisms we are using (like libudev, macOS' I/O registry, SetupDiEnumDeviceInfo on Windows, ...)? I would favor such an approach because it would generate only a fraction of the runtime cost of enumerating all serial devices.