split from #17842 , we split creation of module and activation of it in google style config to separate issues, to simplify integration.

Create a new check GoogleNonConstantFieldNameCheck to enforce non-constant field naming conventions per the Google Java Style Guide §5.2.5.

Background (Reason for new check)

The current MemberName check with regex configuration cannot fully enforce Google Style non-constant field naming rules because it cannot:

1. Correctly enforce Google-specific underscore placement rules
2. Support multipart numeric version suffixes (for example guava33_4_5)
3. Reject special-prefix (Hungarian-style) names such as mValue

Proposed Rules (Non-constant fields only)

• Field names must follow lowerCamelCase
• Single-character field names are not allowed
• Special prefix names (for example mValue, sCount, kSize) are not allowed, per Google Java Style Guide §5.1
• Underscores are allowed only between adjacent digits (multipart version or numbering suffix)
• Leading, trailing or double underscores are not allowed

Scope

This check applies only to non-constant fields:

• Instance fields

Explicitly out of scope

• Constant fields (static final)
• Local variables
• static fields that are not static final

Examples

Valid:

userName
timeoutMs
foo123
guava33_4_5
kotlinVersion1_9_24

Invalid:

f                                    // violation, single character
mValue                         // violation,special prefix not allowed
sCount                         // violation, special prefix not allowed 
foo_bar                        // violation, underscore between letters
gradle_9_5_1               // violation, underscore between letter-digit
kotlin_version1_9_24  // violation, underscore between letters
guava_33_4_5             // violation, underscore between letter-digit
guava33__4_5             // violation, consecutive underscores
guava33_4_5_             // violation, trailing underscore
_foo                               // violation, leading underscore