refactor(motor-control): single source of truth for the MCP command numbers

[finger563]

Single source of truth for the MCP236/266 command numbers

Stacked on #764 (needs the motor_controller component). Rebases onto main once #764 merges.

Follow-up to the design discussion on whether basicmicro (packet serial) and mcp266
(CANopen) could be unified: the right answer is the MotorController concept for the
API, not a merged component — but the one thing genuinely worth de-duplicating is the
command-number table, and this PR does that.

The drift risk

The MCP266's CANopen firmware mirrors the Basicmicro packet-serial command set into its
manufacturer object dictionary at 0x2000 + command. So "read main battery voltage" is
command 24 on serial and object 0x2018 on CAN — the same 24. But mcp266_core.hpp
hardcoded those numbers as magic values (command_object(24), (82), (200),
(61/62/63/64), (32/33/35/36)) that had to be hand-kept in lockstep with
basicmicro's BasicmicroCommand enum. Nothing stopped them drifting.

The change

• Move the BasicmicroCommand table into the shared motor_controller component
  (basicmicro_commands.hpp). Both drivers already depend on that component, so this adds
  no dependency between the two sibling drivers and no new component.
• basicmicro_core.hpp includes it (keeps its packet codecs / CRC / BasicmicroStatus —
  those are transport-specific and not shared).
• mcp266_core.hpp derives every manufacturer object from the named enum via a new
  command_object(BasicmicroCommand) overload, e.g.
  command_object(BasicmicroCommand::ReadMainBatteryVoltage) instead of command_object(24).
  The numbers now live in exactly one place.

No behavior change

Pure relocation + indirection — no object address or command byte changes. Both
host-buildable cores test-verify the same concrete values (the mcp266 test still asserts
0x2018 etc.).

Verified

• basicmicro + mcp266 host tests pass (rebuilt with the added
  -I../../motor_controller/include for the shared header; their build instructions are
  updated accordingly — these are dev tests, not CI-gated).
• Both examples build clean on IDF v6.0.1.

Note: this is the DRY win, not a merge. The transports stay separate components (different
wire protocols, byte order, and control models — CiA 402 state machine vs direct commands);
they share the interface (MotorController) and now the command-number table, which is
all they genuinely have in common.

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The change is a low-risk refactor that centralizes command constants without altering computed indices/values, and the dependency/include updates appear consistent.

Pull request overview

This PR refactors the MCP236/266 motor-control stack to make the Basicmicro/MCP command-number mapping a single source of truth, shared across the packet-serial (basicmicro) and CANopen (mcp266) transports via the motor_controller component.

Changes:

• Introduces a shared espp::detail::BasicmicroCommand enum in motor_controller and updates both transport cores to include it.
• Updates mcp266 to derive manufacturer object indices from named commands (command_object(BasicmicroCommand::...)) instead of hardcoded magic numbers.
• Updates docs and host-test build instructions to reflect the shared header location.

File summaries

File	Description
doc/en/motor_control/motor_controller.rst	Documents the shared BasicmicroCommand table and why mcp266 derives object indices from it.
doc/Doxyfile	Adds the new shared header to Doxygen INPUT so it appears in generated docs.
components/motor_controller/include/basicmicro_commands.hpp	New shared command-number enum (BasicmicroCommand) serving as the single source of truth.
components/mcp266/test/mcp266_host_test.cpp	Updates host-build instructions to include the motor_controller include path.
components/mcp266/include/detail/mcp266_core.hpp	Switches manufacturer-object constants to use BasicmicroCommand and adds an overload command_object(BasicmicroCommand).
components/basicmicro/test/basicmicro_host_test.cpp	Updates host-build instructions to include the motor_controller include path.
components/basicmicro/include/detail/basicmicro_core.hpp	Removes the local BasicmicroCommand definition in favor of the shared header.

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 0
• Review effort level: Lite

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[github-actions]

✅Static analysis result - no issues found! ✅

[Copilot]

🟡 Changes recommended

The component README must document the newly shared command table.

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

Review details

• Files reviewed: 7/7 changed files
• Comments generated: 1
• Review effort level: Balanced