Add port commands for getting Discovered SVIDs, Discover Identity, executing Hard Reset

[asasine]

Depends on

• Add types for Discover Identity structured VDMs embedded-usb-pd#64
• Add methods for registers Get Discovered SVIDs, Received SOP/SOP' Identity Data, executing Hard Reset tps6699x#104

[github-actions]

Cargo Vet Audit Passed

cargo vet has passed in this PR. No new unvetted dependencies were found.

[Copilot]

Pull request overview

Adds new Type‑C/USB‑PD port commands to expose discovered SVIDs, retrieve cached Discover Identity responses (SOP/SOP′), and trigger a Hard Reset through the embedded-services Type‑C controller abstraction and the type-c-service wrapper/driver layers.

Changes:

• Extend the Type‑C controller/external command enums and context APIs with GetDiscoveredSvids, GetDiscoverIdentity* (SOP/SOP′), and HardReset.
• Implement these new controller APIs for the TPS6699x driver and the std mock controller.
• Wire the new external commands through the type-c-service port command handler and PD wrapper.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
type-c-service/src/wrapper/pd.rs	Routes new PortCommandData variants to controller driver calls and returns new PortResponseData variants.
type-c-service/src/service/port.rs	Adds service-level handlers for the new external port commands.
type-c-service/src/driver/tps6699x.rs	Implements controller trait methods for discovered SVIDs, hard reset, and Discover Identity response retrieval.
examples/std/src/lib/type_c/mock_controller.rs	Extends the mock controller to satisfy the updated Controller trait.
embedded-service/src/type_c/external.rs	Adds new external command/response variants and helper functions for the new APIs.
embedded-service/src/type_c/controller.rs	Adds DiscoveredSvids type, new controller trait methods, lookup helper, and ContextToken APIs.
Cargo.lock	Updates lockfile for dependency revisions (notably embedded-usb-pd and tps6699x).