Add Application Signals logs pipeline translator

[jj22ee]

Description of the issue

Application Signals currently collects metrics and traces but not logs. This PR adds a CWAgent translator that generates an OTel logs pipeline to route OTLP logs to CloudWatch via the CW OTLP endpoint, with automatic per-service log group creation.

Customers configure logs.logs_collected.application_signals with optional log_group_name (supporting placeholders like {service.name}) and log_stream_name. The provisioner extension creates log groups/streams on first encounter.

Description of changes

Adds a new pipeline translator at translator/translate/otel/pipeline/applicationsignalslogs/ that produces two pipeline shapes:

Dynamic (placeholders in log_group_name/log_stream_name):

• Auth chain: otlphttp → headers_setter → awscloudwatchlogsprovisioner → sigv4auth
• Processors: transform → attributestocontext → batch(metadata_keys)

Static (no placeholders):

• Auth chain: otlphttp → awscloudwatchlogsprovisioner → sigv4auth
• Processors: batch
• Static x-aws-log-group/x-aws-log-stream headers on the exporter

Notable behaviors:

• Multiple placeholders supported in both group and stream (e.g. /{deployment.environment}/prefix/{service.name})
• Customer-set resource attributes take priority over template (OTTL where guard)
• AutoEnableIfNeeded auto-opts-in the logs pipeline when metrics_collected.application_signals is configured

New/Updated shared translator packages:

• extension/awscloudwatchlogsprovisioner — new
• extension/headerssetter — new
• processor/attributestocontext — new
• exporter/otlphttp — new (generic, signal-aware EndpointConfig)
• extension/sigv4auth — Updated with WithService option
• processor/batchprocessor — Updated with WithMetadataKeys option
• processor/transformprocessor — Updated with NewTranslatorWithLogStatements

License

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Tests

• Unit tests
• Integration tests in amazon-cloudwatch-agent-test: <TODO: Make PR>

Requirements

Before commiting your code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

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Integration Tests

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[jj22ee]

go.mod will be updated since this PR depends on:

• pull/521 - Cherry-picks for extension/headersetter
• pull/510 - attributestocontext
• pull/511 - awscloudwatchlogsprovisioner
• pull/506- EMF Exporter enhancement

[jj22ee]

Still pending and not final.

[jj22ee]

These key values are not following any otel spec, they're just arbitrary attributes created by Transform Processor which are used by AttributesToContext Processor, so we don't expect customers to know about these keys or even set them in their exported logs.

However, if customer does know and set these these attributes in their logs, we'll respect it and won't override them.