cleanup: remove headscale

[kerthcet]

What this PR does / why we need it

Which issue(s) this PR fixes

Fixes #

Special notes for your reviewer

Does this PR introduce a user-facing change?

[Copilot]

Pull request overview

This PR removes the previously implemented headscale/SandD access channel integration and all associated AWS bootstrap, manager wiring, Kubernetes manifests/samples, and documentation, leaving the codebase without the headscale/keybroker-based tunnel mechanism.

Changes:

• Removes SandD key-minting client code, headscale keybroker service, and related tests.
• Simplifies AWS provider bootstrap/user-data generation and provider constructors by deleting SandD-specific logic/parameters.
• Deletes the config/sandd overlay + samples and removes deploy-time substitution logic and third-party notice references tied to that integration.

Reviewed changes

Copilot reviewed 25 out of 26 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
THIRD_PARTY_NOTICES.md	Removes Tailscale-related third-party notice that was specific to the SandD channel.
README.md	Removes reference to third-party notices file from the License section.
pkg/sandd/keybroker.go	Deletes the broker client used for key minting.
pkg/sandd/keybroker_test.go	Deletes tests for the broker client.
pkg/provider/provider.go	Removes SandD-related provider-agnostic types/interfaces.
pkg/provider/aws/translate.go	Removes SandD bootstrap injection and related constants/shim logic; keeps plain docker-run mapping.
pkg/provider/aws/sandd_test.go	Deletes AWS provider tests covering SandD key minting and injection behavior.
pkg/provider/aws/client.go	Removes SandD config parameter from AWS provider construction.
pkg/provider/aws/client_test.go	Removes SandD-enabled bootstrap tests; keeps/renames plain bootstrap test.
pkg/provider/aws/aws.go	Removes SandD fields/state and per-instance SandD resolution logic from the AWS provider.
Makefile	Removes keybroker image build/push targets and deploy-time substitution flow.
hack/deploy.sh	Removes SANDD_TUNNEL_SERVER plumbing passed into make deploy.
Dockerfile.keybroker	Deletes the keybroker container image definition.
config/sandd/README.md	Deletes SandD overlay documentation.
config/sandd/manager-config.yaml	Deletes SandD manager ConfigMap overlay.
config/sandd/kustomization.yaml	Deletes SandD overlay kustomization.
config/sandd/headscale.yaml	Deletes headscale + keybroker sidecar deployment manifests.
config/samples/sandd-controller.yaml	Deletes the SandD controller sample manifest.
config/samples/headscale-service.yaml	Deletes the headscale LoadBalancer Service sample manifest.
config/manager/manager.yaml	Removes required envFrom ConfigMap reference for SandD wiring.
config/default/kustomization.yaml	Removes ../sandd overlay inclusion and updates patch scoping comments.
cmd/main.go	Removes SandD wiring/env usage and updates AWS provider registration call signature.
cmd/keybroker/main.go	Deletes the keybroker HTTP service implementation.
cmd/keybroker/main_test.go	Deletes keybroker tests.
.env.example	Removes SandD endpoint documentation/variable from the example env file.

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[Copilot]

Pull request overview

Copilot reviewed 25 out of 26 changed files in this pull request and generated no new comments.

[kerthcet]

/lgtm
/kind cleanup

[InftyAI-Agent]

Approved: PR has both lgtm and approved labels