[maint]: reduce duplicate `→zinit-extract` declaration in ziextract case statement

[vladdoster]

Summary

ziextract case statement should set variable that is used as function body for →zinit-extract in a singular place in ziextract to be DRY

Proposed fix

No response

[vladdoster]

@claude can you provide a solution that solves issue and keeps LOC same or reduces it.

[anthropic-code-agent]

The agent encountered an error and was unable to start working on this issue: Please try again later, or contact support if the problem persists. (Request id: E266:D7A3F:18C8D02:2156B52:6A498ED2)

[openai-code-agent]

The agent encountered an error and was unable to start working on this issue: Please try again later, or contact support if the problem persists. (Request id: E266:D7A3F:18D5C50:2168283:6A498F30)

[vladdoster]

@claude can you provide a solution that solves issue and keeps LOC same or reduces it.