enhancement(aws_ec2_metadata transform): support additional IMDS categories

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Summary

This PR extends the aws_ec2_metadata transform to support additional IMDS instance metadata categories, as requested in #22069. The following fields can now be requested via the fields option:

• availability-zone-id (placement/availability-zone-id) — unlike the availability zone name, the AZ ID is consistent across AWS accounts, which is useful for correlating zonal impact in multi-account deployments.
• partition (services/partition)
• domain (services/domain)
• placement-group-name (placement/group-name)
• placement-partition-number (placement/partition-number)
• host-id (placement/host-id) — useful for identifying bad Dedicated Hosts (e.g. EC2 Mac instances).
• autoscaling-target-lifecycle-state (autoscaling/target-lifecycle-state) — useful for correlating EC2 Auto Scaling lifecycle hook events with on-instance events.

Each new field follows the existing pattern for optional categories (such as account-id and tags): it is opt-in and only fetched when explicitly listed in fields. The default field allowlist is unchanged, so there is no change in behavior or additional IMDS requests for existing configurations.

Vector configuration

transforms:
  ec2_meta:
    type: aws_ec2_metadata
    inputs: ["in"]
    fields:
      - "instance-id"
      - "availability-zone-id"
      - "partition"
      - "domain"
      - "placement-group-name"
      - "placement-partition-number"
      - "host-id"
      - "autoscaling-target-lifecycle-state"

How did you test this PR?

• cargo check --lib --no-default-features --features transforms-aws_ec2_metadata — passes
• cargo test --lib --no-default-features --features transforms-aws_ec2_metadata aws_ec2_metadata — passes
• cargo fmt --check — passes
• cargo clippy --lib --no-default-features --features transforms-aws_ec2_metadata -- -D warnings — passes

The new categories are all simple flat IMDS GET endpoints fetched through the existing get_metadata helper (which already handles IMDSv2 tokens and 404 responses by skipping the field), so they reuse the transform's existing token/refresh/error-handling logic. IMDS paths were verified against the AWS EC2 instance metadata categories documentation.

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

• Closes: Transforms – AWS EC2 Metadata – Support Additional IMDS Instance Metadata Categories #22069

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