REST API: SetVoltage

[jbride]

HTTP Put API to set voltage on a board

Path = "/api/v1/board/{serial}/voltage",
Response: JSON representation of SetVoltageResponse:

---

#[derive(Debug, Clone, Deserialize, Serialize, ToSchema)]
pub struct SetVoltageResponse {
    /// Whether the operation was successful
    #[schema(example = true)]
    pub success: bool,
    /// The requested voltage in volts
    #[schema(example = 1.2)]
    pub requested_voltage: f32,
    /// The actual voltage readback in volts (if successful)
    #[schema(example = 1.198)]
    pub actual_voltage: Option<f32>,
    /// Error message (if any)
    #[schema(example = "Voltage set to 1.200V (readback: 1.198V)")]
    pub message: Option<String>,
}

---

[rkuester]

MIP-0001 reframes the API as one addressable tree, so setting voltage becomes a write to the board's target_voltage_v setpoint rather than a dedicated endpoint. Folding this into #57; closing as superseded. Thanks for speccing it out.