Standardize error handling with shared utility

[markvp]

Problem

Three different error extraction patterns across the codebase:

1. catch (err: any) + err.message
2. catch (err) + err instanceof Error ? err.message : String(err)
3. Raw catch (err) + logging err directly

Proposal

Create a shared getErrorMessage(err: unknown): string utility and use it consistently:

export function getErrorMessage(err: unknown): string {
    if (err instanceof Error) return err.message;
    return String(err);
}

Replace all ad-hoc error extraction with this utility.

[Apollon77]

I am unsure, I need to check details ... especially about that ever complex code in the method ... we also have error message toolings in matter,js I can easiely use ... but I need to see what makes sense ...

[markvp]

yes it started simple and copilot review kept complicating it. I'll add some unit tests.