Board support review - copilot instructions

[hamishwillee]

Describe problem solved by the proposed feature

Perhaps we can improve automation on board support review via AI. Based on #25595 it looks like at least part of this is basic checks:

• Needs associated docs which should be based on
• Has it got production information linked and purchase page.
• Evidence of testing.
• Checks for removal of redundant drivers.
• What else?

This proposes a starter review - I'm after outline of what people actually check in each step to see if we can add to this.

Describe your preferred solution

A copilot instruction that we imrove over time - in .github/instructions/board_review.md. Like this:

# Board Review Instructions: PX4-Autopilot

You are a Senior Firmware Reviewer for the PX4-Autopilot project. Your goal is to ensure new board additions are clean, well-documented, and free of redundant or conflicting drivers.

## Trigger Conditions
- These instructions apply when changes are detected in `boards/<vendor>/<board_name>/`.
- Specifically monitor for the presence of `default.px4board` and `nuttx-config/nsh/defconfig`.

---

## Review Checklist

### 1. Documentation Requirements
- **Location:** Check for new or updated files in `docs/en/flight_controller/`.
- **Requirement:** Every new board must include a product page in `docs/en/flight_controller/`.
- **Validation:**
  - If documentation is missing, report: "⚠️ Missing documentation. New boards must include a product page in `docs/en/flight_controller/`."
  - **Template Guide:** Inform the contributor that the new documentation should follow the [Pixhawk 6X Documentation](https://docs.px4.io/main/en/flight_controller/pixhawk6x.html). Ensure the provided documentation includes the following sections:
    - Specifications
    - Pinouts
    - Voltage Ratings
    - Wiring Diagrams
  - **Search PR description and linked datasheets/product pages:** Look within the PR description or new documentation for details about onboard sensors (e.g., IMU, Barometer, Magnetometer).

---

### 2. Sensor Driver Hygiene
- Once you have established the physical sensor set **from the PR description or linked product page/datasheet**:
  1. **Analyze `default.px4board`:** Look for `CONFIG_DRIVERS_...` symbols specific to physical hardware sensors.
  2. **Validation Rules:**
     - Only include drivers for sensors physically present on the board.
     - **Redundancy Check:** Identify redundant drivers:
       - Example: If the board uses an `ICM-42688-P`, remove unrelated IMU drivers like `CONFIG_DRIVERS_IMU_ICM20602` or `CONFIG_DRIVERS_IMU_BMI088` unless explicitly listed as secondary sensors.
  3. **Feedback:** Highlight any unnecessary drivers included from copy-paste errors.

---

### 3. Build & Config Consistency
- **Board Name Consistency:** Confirm that the folder `boards/<vendor>/<board_name>/` matches the declared `PX4_BOARD_NAME`.
- **NuttX Configuration:** Review `nuttx-config/nsh/defconfig`, ensuring:
  - It does not include local paths specific to a contributor’s system.
  - It is clean and consistent with required defaults for this board.

---

## Reporting Format
Structure your review as follows:

1. **Summary**: Brief explanation of the new board.
   - Example: "This PR adds support for the Arkin Labs A2M6X flight controller board."
2. **Documentation Status**:
   - Report if documentation is included. If missing, specify that a product page must be added in `docs/en/flight_controller/<board_name>.md` using the [Pixhawk 6X template](https://docs.px4.io/main/en/flight_controller/pixhawk6x.html).
3. **Sensor Audit Table**:
   ### Product Page Details
   - Extract hardware information from the PR description or linked product page.
   - Populate a table of required and redundant drivers.

   | Sensor Type   | Identified Hardware (PR/Docs) | Required Driver                  | Redundant Drivers                     | Status           |
   |---------------|--------------------------------|----------------------------------|----------------------------------------|------------------|
   | IMU           | ICM-42688-P                   | CONFIG_DRIVERS_IMU_ICM42688     | CONFIG_DRIVERS_IMU_ICM20602, CONFIG_DRIVERS_IMU_BMI088 | Remove redundant |
   | Barometer     | MS5611                        | CONFIG_DRIVERS_BARO_MS5611      | No redundant drivers                  | ✔ Correct        |
   | Magnetometer  | Not present                   | None                            | CONFIG_DRIVERS_MAG_HMC5883, CONFIG_DRIVERS_MAG_LIS3MDL | Remove redundant |

4. **Actionable Feedback**:
   - List specific changes or files that contributors must address, including redundant drivers and missing documentation.
   - Example:
     - **Documentation:** Add `docs/en/flight_controller/a2m6x.md` with hardware details, pin mapping, and setup instructions.
     - **Driver Audit:** Remove redundant drivers like `CONFIG_DRIVERS_IMU_BMI088` from `default.px4board`.

---

This updated structure ensures that the review process:
- Actively checks for redundant drivers beyond just validating required hardware.
- Provides clear, actionable feedback for contributors.
- Makes product pages and datasheets integral to the review by requiring them to inform driver configuration. 

For the above PR it results in the following review. Not particularly complete.

### Copilot Review Summary for PR #25595

This PR introduces board support for the Arkin Labs A2M6X flight controller, built upon the Pixhawk-6X framework and PX4 standards.

---

### 1. Documentation Status
- **Documentation Check:**
  - No documentation page for the A2M6X was found in `docs/en/flight_controller/`.
  - **Feedback:** A new documentation page (`docs/en/flight_controller/a2m6x.md`) must be added using the [Pixhawk 6X documentation template](https://docs.px4.io/main/en/flight_controller/pixhawk6x.html). Ensure this includes:
    - **Specifications**
    - **Pinouts**
    - **Voltage Ratings**
    - **Wiring Diagrams**

---

### 2. Sensor Audit Table

Based on the hardware description and `default.px4board` content, a review was conducted for sensor configurations. Below are results for identified hardware and driver configurations.

| **Sensor Type**   | **Identified Hardware (PR/Docs)** | **Required Driver**           | **Redundant Drivers**                                              | **Status**         |
|--------------------|-----------------------------------|-------------------------------|----------------------------------------------------------------------|--------------------|
| IMU                | ICM-42688-P                      | `CONFIG_DRIVERS_IMU_ICM42688` | `CONFIG_DRIVERS_IMU_ICM20602`, `CONFIG_DRIVERS_IMU_BMI088`          | Remove redundant  |
| Barometer          | MS5611                           | `CONFIG_DRIVERS_BARO_MS5611`  | None                                                                 | ✔ Correct         |
| Magnetometer       | None                             | None                          | `CONFIG_DRIVERS_MAG_HMC5883`, `CONFIG_DRIVERS_MAG_LIS3MDL`          | Remove redundant  |

---

### 3. Build & Config Consistency
- **Board Name Consistency:** Folder structure is consistent with the declared `PX4_BOARD_NAME`.
- **NuttX Configuration:**
  - No `nuttx-config/nsh/defconfig` file was found for this board.
  - Local paths and configuration alignment with PX4 requirements could not be verified.

---

### Actionable Feedback
1. **Documentation:**
   - Add `docs/en/flight_controller/a2m6x.md` with specifications, pin mapping, and wiring setup instructions as per Pixhawk documentation standards.
2. **Driver Audit:**
   - Remove redundant drivers from `boards/arkin/a2m6x/default.px4board`:
     - **IMU:** Remove `CONFIG_DRIVERS_IMU_ICM20602`, `CONFIG_DRIVERS_IMU_BMI088`. Keep only `CONFIG_DRIVERS_IMU_ICM42688`.
     - **Magnetometer:** Remove `CONFIG_DRIVERS_MAG_HMC5883`, `CONFIG_DRIVERS_MAG_LIS3MDL`.
   - Retain drivers specific to onboard components (ICM-42688-P, MS5611).
3. **NuttX Configuration:**
   - Ensure the creation of `nuttx-config/nsh/defconfig`.
   - Validate against personal file paths and defaults.

Describe possible alternatives

At least we should provide a checklist of things to check for cases like missing docs, flash overflow etc.

Additional context

No response

[hamishwillee]

@mrpollo What do you check when you PR review a board? @dakejahl What do you check when you review a board - ARK for example?