[bug] it is not possible to use context:0 ... N

[mpet]

Describe the bug

We only wanted to see a summary for matching lines.

When using context:0 ... N in the search field
we get a crash in webserver.

To reproduce

I tried:

Helpers context:0

or

Helpers context:1

Both failed.

Sourcebot deployment information

Sourcebot version:

Current version: v5.0.3(496b09a)

Additional information

No response