feat(): report gateway tunnel connectivity to hub WorkerSliceGateway status (#471)

[Shreesha001]

Each worker now reports the connection state of every gateway link to the hub, so the controller can tell if the slice topology is healthy.

For each WorkerSliceGateway it sets:

• ConnectionState: Connected (tunnel up), NotConnected (down), or Pending (not up yet).
• LastTransitionTime: updated only when the state changes.
• Re-checked every ~30s so it stays current.

Note: the issue suggested a peerStatuses array + summary counts, but KubeSlice already has one WorkerSliceGateway per link, so the state lives on each object instead. The ready/failing counts are computed on the controller side.

Addresses #471

How Has This Been Tested?

On a 4-cluster kind setup with a Hub-and-Spoke slice:

• Tunnel up → status shows Connected.
• Gateway pods down → status shows NotConnected.
• Before tunnel is up → status shows Pending.
• LastTransitionTime changes only on state change.
• Unit test for the state logic (deriveGatewayConnectionState).

Checklist:

• The title of the PR states what changed and the related issues number.
• Does this PR requires documentation updates?
• I've updated documentation as required by this PR.
• I have ran go fmt
• I have updated the helm chart as required by this PR.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested it for all user roles.
• I have added all the required unit test cases.
• I have verified the E2E test cases with new code changes.
• I have added all the required E2E test cases.

Does this PR introduce a breaking change?

NONE