fix: UpdateOneDoc should update documents instead of deleting them

[kael-developer]

Summary

Fixes #3 — UpdateOneDoc in sharedlib/docliteexport.go was silently deleting documents instead of updating them.

Root Cause

The function called collection.DeleteOne(id) and completely ignored the doc parameter:

func UpdateOneDoc(id int64, doc string, name string) {
    collection := getColFromName(name)
    collection.DeleteOne(id)
}

Fix

Updated the function to follow the same pattern as Insert:

1. Unmarshal the doc JSON string into map[string]interface{}
2. Return early if unmarshaling fails
3. Call collection.UpdateOneDoc(id, document) instead of collection.DeleteOne(id)

func UpdateOneDoc(id int64, doc string, name string) {
    collection := getColFromName(name)
    document := make(map[string]interface{})
    err := json.Unmarshal([]byte(doc), &document)
    if err != nil {
        return
    }
    collection.UpdateOneDoc(id, document)
}

Acceptance Criteria Met

• ✅ UpdateOneDoc unmarshals the doc string parameter into map[string]interface{}
• ✅ UpdateOneDoc calls collection.UpdateOneDoc(id, document) instead of collection.DeleteOne(id)
• ✅ If JSON unmarshaling fails, the function returns early (same pattern as Insert)
• ✅ No changes to the C header — the signature is already correct
• ✅ The fix follows the same code style as the existing Insert function

Files Changed

• sharedlib/docliteexport.go — Fixed UpdateOneDoc function body