fix(types): allow omitted defaulted queries

[bytaesu]

closes #15

[greptile-apps]

Greptile Summary

This PR corrects schema optionality inference so query options may be omitted when the schema supplies a default.

• Checks the inferred schema input for undefined rather than checking the schema object itself.
• Adds runtime coverage confirming that an omitted query receives its schema-defined default.

Confidence Score: 5/5

The PR appears safe to merge, with no outstanding or newly introduced issues identified.

No changes were made after the previous review, and all three previous findings were manually resolved without explanatory replies.

_{Reviews (6): Last reviewed commit: "fix(fetch): preserve existing header val..." | Re-trigger Greptile}

[bytaesu]

@greptileai review