chore(runner): First cut on Tekton pipeline detection

[javirln]

This PR adds automatic detection and metadata collection for Tekton Pipelines CI/CD environment.

Changes

• Added TEKTON_PIPELINE runner type to the protobuf schema
• Implemented Tekton runner with filesystem-based detection via /tekton/results directory
• Registered runner in factory for automatic environment discovery

Detection Strategy

The Tekton runner detects execution environments by checking for the presence of Tekton's /tekton/results directory, which is mounted in all TaskRun and PipelineRun containers. This approach works reliably for both standalone TaskRuns and tasks within Pipelines.

Metadata Collection via Kubernetes Downward API

TBD in a separated PR

Tackles issue #2545

[migmartri]

ptal at the test error, and the spurious descriptor.ts

So in the end we have access to env vars and dashboards or am I understanding this incorrectly? Do you have a demo of the env?

[waveywaves]

Tekton doesn't add labels through downward API, so it might be good to use the service account directly.