feat(OBE-9898): always require a token, read site_version from claim

[saurabhchauhan-s1]

The vector source's auth drops the require_token config knob: a valid bearer token is now always required, removing the legacy require_token=false bypass that accepted unauthenticated pushes. The site's version is read from the validated JWT's site_version claim (stamped by the manager auth-service, OBE-9896) and logged for telemetry / future per-version policy.

• jwt_auth.rs: remove AuthConfig.require_token, default_require_token, Inner.require_token; authenticate() rejects a missing authorization header unconditionally; read SITE_VERSION_CLAIM from the decoded claims.
• sources/vector/mod.rs: delete the legacy and now-redundant require_token tests, rename the kept ones to the unconditional behavior.
• test_util/jwt_auth.rs: drop require_token from the shared build_auth helper.

Summary

Vector configuration

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Change Type

• Bug fix
• New feature
• Dependencies
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

Notes

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