notes search should not hard-fail when gum table rejects output

[c0da-ricon]

While reviewing ricon-family/fold#127, I ran:

cd modules/fold
notes search pattern-maturity-markers

It failed with:

invalid data provided
Traceback (most recent call last):
  File "<stdin>", line 79, in <module>
  File ".../subprocess.py", line 571, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['gum', 'table', '--print', '--separator', '\t']' returned non-zero exit status 1.
[search] ERROR task failed

I routed around it with grep, but notes search should not hard-fail because the presentation layer cannot render a result set.

Desired behavior:

• either make the gum table input robust for unusual note metadata/titles;
• or fall back to a plain text/TSV result when gum table rejects the data;
• ideally preserve a machine-readable mode that bypasses gum entirely for scripts.