Default value on field is overwriting default value on useAppForm

Describe the bug

As mentioned in the title if you have a default value on a form.AppField this overwites the value coming from useAppForm for async loading. Hierarchically these should be overwritten from parent.

Prio

1. useAppForm defaultValue
2. formOptions defaultValue
3. form.AppField defaultValue

Your minimal, reproducible example

https://codesandbox.io/p/sandbox/frosty-james-mwktlf

Steps to reproduce

1. Create a useAppForm with defaultValue
2. Declare an empty string or countryCode for a field as default value if no value exists
3. Have defaultValue from base
4. Expect defaultValue change on root to overwrite fieldDefaultValue

Expected behavior

Expect defaultValue change on root to overwrite fieldDefaultValue

How often does this bug happen?

None

Screenshots or Videos

No response

Platform

Windows
Chrome 136.0.7103.114

TanStack Form adapter

None

TanStack Form version

^1.11.1

TypeScript version

^5.8.3

Additional context

No response

Start with the linked CodeSandbox reproduction and trace how default values from useAppForm, formOptions, and form.AppField are combined during async loading. Verify the precedence described in the issue, with a root useAppForm defaultValue overriding the field-level defaultValue when it changes.