hidi2c: fix command protocol

[williampMSFT]

This change fixes two bugs in the HID-I2C command protocol:

1. In the GET_REPORT path, we weren't listening for a read request before responding with the report payload. On some HALs, this causes the bytes you write to be dropped and never get transmitted over the bus.
2. In the SET_REPORT path, when not using implicit report IDs, the host actually writes the report ID twice; once in the command register and again in the data register. We were not accounting for the second write as the first byte in the data register.

[Copilot]

🟡 Changes recommended

The new GET_REPORT pre-listen does not validate that the next bus event is actually a read request, which can lead to incorrect behavior/timeouts on unexpected request types.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Fixes HID-I2C command protocol handling in the target service to better match host/HAL transaction ordering and report payload formatting requirements.

Changes:

• GET_REPORT: wait for a controller read request before attempting to respond with the report payload.
• SET_REPORT: when report IDs are not implicit, skip the duplicated report ID byte present in the data-register payload.

File summaries

File	Description
hidi2c-target-service/src/service.rs	Adjusts GET_REPORT response sequencing and SET_REPORT payload parsing to match HID-I2C command protocol expectations.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 1
• Review effort level: Lite

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