Add TimestampedGrantedAuthority for time-based authorization

[yybmion]

Adds TimestampedGrantedAuthority to support time-based authorization rules as described in #17864 .

Changes

• New TimestampedGrantedAuthority class implementing GrantedAuthority
• Builder pattern with temporal fields: issuedAt, notBefore, expiresAt
• Add serialization sample and generated .serialized file
• Comprehensive test coverage

Usage

// Authority that expires after 5 minutes
GrantedAuthority authority = TimestampedGrantedAuthority
    .withAuthority("profile:read")
    .expiresAt(Instant.now().plusSeconds(300))
    .build();

Fixes #17864

[yybmion]

I think the build failure appears to be related to serialization tests(SpringSecurityCoreVersionSerializableTests) - TimestampedGrantedAuthority is a new class without existing serialized files from previous versions. How should this be handled?

[jzheaux]

@yybmion thanks for the PR and for double-checking regarding serialization. Can you please add the following to the PR:

1. Favor a random value for the serialization id
2. Add a sample construction to SerializationSamples
3. Enable the test SpringSecurityCoreVersionSerializableTests#serializeCurrentVersionClasses and run it. This will generate the needed file.
4. Re-disable the test

In the end, there should be three file changes in your PR: The new authority implementation, a .serialized file, and SerializationSamples.

[yybmion]

Thanks for the guidance @jzheaux. I’ve added the .serialized file and pushed the changes.