ECS Managed Instances - Parse ECS /tasks metadata endpoint

[stzou]

What does this PR do?

Adds support for parsing the ECS /tasks metadata endpoint on ECS Managed Instances, and wires the new DaemonName field through to workloadmeta and the orchestrator transformer.

pkg/util/ecs/metadata/v3or4

• Add DaemonName string to the Task struct (populated from the new DaemonName field in the /tasks response, analogous to ServiceName)
• Add tasksMetadataPath = "/tasks" constant and GetTasks(ctx) ([]Task, error) to the Client interface and implementation — calls ${ECS_CONTAINER_METADATA_URI_V4}/tasks to return all host tasks in a single call

comp/core/workloadmeta

• Add DaemonName string to the ECSTask entity in def/types.go
• Wire DaemonName: task.DaemonName in ParseV4Task (collectors/util/ecs_util.go)

comp/core/workloadmeta/collectors/internal/ecs

• Add parseTasksFromV4TasksEndpoint: fetches all host tasks via GetTasks() in a single call and parses them with ParseV4Task. This replaces the v1-enumerate + per-task-v4-fetch pattern.
• setTaskCollectionParserForDaemon: selects parseTasksFromV4TasksEndpoint when running on Managed Instances with a v4 endpoint available

pkg/collector/corechecks/cluster/orchestrator/transformers/ecs/task.go

• Wire DaemonName: task.Task.DaemonName in ExtractECSTask to populate the agent-payload proto field

go.mod

• Bump agent-payload to pick up daemonName = 22 in the ECSTask proto (agent-payload PR #456)

Motivation

With the release of Daemon Scheduling on ECS Managed Instances, AWS has added a new host-level /tasks endpoint that returns all tasks on the host, including a DaemonName field for daemon tasks.

This is the agent-side prerequisite for correct ecs_daemon_name, daemon_arn, and task_definition_arn tagging in the backend.

Describe how you validated your changes

Unit tests added for:

• GetTasks client method (client_test.go)
• parseTasksFromV4TasksEndpoint in the ECS workloadmeta collector (v4parser_test.go, daemon_parser_test.go)
• ExtractECSTask with DaemonName populated (task_test.go — existing tests still pass)

Additional Notes

• The /tasks endpoint has no WithTags variant, so EC2 resource tags are not collected via this path. This is expected — HasEC2ResourceTags() returns false on Managed Instances.

[agent-platform-auto-pr]

Files inventory check summary

File checks results against ancestor 1dfe3dab:

Results for datadog-agent_7.78.0~devel.git.493.7b72a79.pipeline.101754328-1_amd64.deb:

No change detected

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