The field object literal was missing the isEqual property in its
initial definition, causing TypeScript to fail when it was assigned later.

Add isEqual: tripleEquals to the initial field object to match the
InternalFieldState type.

Fixes TypeScript compilation broken by #480.

The field object literal was missing the isEqual property in its
initial definition, causing TypeScript to fail when it was assigned later.

Add isEqual: tripleEquals to the initial field object to match the
InternalFieldState type.

Fixes TypeScript compilation broken by #480.

The field object literal was missing the isEqual property in its
initial definition, causing TypeScript to fail when it was assigned later.

Add isEqual: tripleEquals to the initial field object to match the
InternalFieldState type.

Fixes TypeScript compilation broken by #480.

Co-authored-by: Erik Rasmussen <[email protected]>

Integrated upstream changes:
- PR final-form#480: Improved isEqual register initialization
- PR final-form#517: Fixed TypeScript isEqual errors

Preserved async validation tracking:
- instanceId for stable field instance tracking
- asyncValidationCount and asyncValidationKey

The merge keeps the upstream's robust isEqual initialization logic
while maintaining the per-field async validation tracking needed
to prevent race conditions.

* Migrate from bundlesize to size-limit

Replace bundlesize with size-limit to resolve iltorb compilation issues.

- Remove: bundlesize (depends on unmaintained iltorb)
- Add: @size-limit/preset-small-lib and size-limit
- Configure: Track 4 build outputs (umd.min, umd, es, cjs) with 3kB limits

This follows the same pattern as react-final-form #1056.

Part of OSS-28: Migrate all libraries from bundlesize to size-limit

* Address CodeRabbit feedback

1. Update Node version requirement to >=18 (size-limit requires ^18.0.0 || >=20.0.0)
2. Add size-limit check to CI workflow
   - New 'size' job that builds and runs size-limit
   - Ensures bundle size limits are enforced in CI

* Update yarn.lock for size-limit dependencies

* Fix TypeScript error in isEqual initialization

The field object literal was missing the isEqual property in its
initial definition, causing TypeScript to fail when it was assigned later.

Add isEqual: tripleEquals to the initial field object to match the
InternalFieldState type.

Fixes TypeScript compilation broken by #480.

* Adjust size-limit thresholds to match actual bundle sizes

Current bundle sizes (brotli compressed):
- umd.min: ~6 kB (limit: 7kB with headroom)
- umd: ~6 kB (limit: 7kB with headroom)
- es: ~5.5 kB (limit: 6kB with headroom)
- cjs: ~5.75 kB (limit: 6kB with headroom)

Limits set with ~1kB headroom to catch regressions.

---------

Co-authored-by: Erik Rasmussen <[email protected]>