feat: add GenServer behaviours with options_schema callbacks

[jimsynz]

Summary

• Add BB.Controller, BB.Sensor, and BB.Bridge behaviours with optional options_schema/0 callbacks
• Extend BB.Actuator with the same pattern
• Each behaviour's __using__/1 macro now includes use GenServer, simplifying implementations
• Add ValidateChildSpecs verifier for compile-time validation of child spec options against module schemas
• Merge BB.Parameter.Protocol into BB.Bridge for a cleaner API
• Move disarm/1 callback from BB.Safety to BB.Actuator and BB.Controller behaviours

Usage

defmodule MyActuator do
  use BB.Actuator,
    options_schema: [
      pin: [type: :pos_integer, required: true],
      frequency: [type: :pos_integer, default: 50]
    ]

  @impl BB.Actuator
  def disarm(opts), do: :ok

  @impl GenServer
  def init(opts), do: {:ok, opts}
end

For modules with complex schemas, define the callback explicitly:

defmodule MyController do
  use BB.Controller

  @impl BB.Controller
  def options_schema do
    Spark.Options.new!([...])
  end
end

Test plan

• All 488 tests pass
• Dialyzer passes
• Credo passes
• Updated servo driver packages compile against new API