worker client flow for register

[yussufsh]

This PR implements worker join subcommand to register the worker with the remote control-plane.

1. Sets up Caddy pod for registering routes
2. Registers with the control-plane and start the stream connection.

Will take up other custom arguments ie. certificates, domain name, etc. in future.

TODO: dispatch cmd to the local runtime executor.

[yussufsh]

Control-plane register:

[root@onprem133721154 ai-services]# ./bin/ai-services-linux-ppc64le catalog worker list
ID                                     NAME   RUNTIME   STATUS         LAST HEARTBEAT
52b40d8c-88e2-4c5d-9915-4451ac2f7943   d      unknown   disconnected   -
3e7ee33e-742b-4185-8fcb-af8feb2c76e4   3      podman    ready          2026-08-21T11:27:18Z

Worker join:

[root@onprem133728235 ai-services]# ./bin/ai-services-linux-ppc64le worker join 10.20.179.49:9090 --runtime podman --token 1c2179c7-7e65-423f-96cf-71c1c1306b4d
Starting worker join — press Ctrl-C to stop.
Setting up worker Caddy proxy...
worker caddy: Caddyfile written to /var/lib/ai-services/worker/caddy/Caddyfile
worker caddy: deploying ai-services--worker-caddy
'caddy.yaml.tmpl', 'ai-services--worker-caddy': Starting Pod Readiness check...
'caddy.yaml.tmpl', 'ai-services--worker-caddy': Performing Containers Creation check for pod...
'caddy.yaml.tmpl', 'ai-services--worker-caddy': Waiting for Containers Creation... Timeout set: 5m0s
'caddy.yaml.tmpl', 'ai-services--worker-caddy': Containers creation check for pod is completed
'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'ai-services--worker-caddy-caddy': Performing Container Readiness check...
'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'ai-services--worker-caddy-caddy': Waiting for Container Readiness... Timeout set: 2m5s
'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'ai-services--worker-caddy-caddy': Readiness Check for the container is completed!
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'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'f4f20e5ff47b-infra': Performing Container Readiness check...
'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'f4f20e5ff47b-infra': Waiting for Container Readiness... Timeout set: 2m0s
'caddy.yaml.tmpl', 'ai-services--worker-caddy', 'f4f20e5ff47b-infra': Readiness Check for the container is completed!
-------
'caddy.yaml.tmpl', 'ai-services--worker-caddy': Pod has been successfully deployed and ready!
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Worker Caddy proxy is ready.
Connecting to catalog gateway at 10.20.179.49:9090...
Registering worker with catalog control plane...
Worker "3" registered with control plane.
Opening CommandStream for worker "3"...
CommandStream open for worker "3".

[mayuka-c]

Rest LGTM

[mayuka-c]

Rest LGTM

[mayuka-c]

LGTM