Documentation: add micro-ROS integration guide

Documentation/components/index.rst

@@ -31,3 +31,4 @@ case, you can head to the :doc:`reference <../reference/index>`.
    video.rst
    crypto.rst
    wireless.rst
+   microros/index.rst

Documentation/components/microros/index.rst

@@ -0,0 +1,55 @@
+============
+micro-ROS
+============
+
+Phase 2: Library Skeleton
+==========================
+
+This phase establishes the foundational library structure for micro-ROS integration in Apache NuttX.
+
+Structure
+---------
+
+The micro-ROS library is located in ``apps/system/microros/`` with the following components:
+
+- ``Make.defs`` — Build configuration
+- ``Kconfig`` — Configuration options
+- ``Makefile`` — Build orchestration
+- ``.gitignore`` — Excluded build artifacts
+
+Configuration Options
+---------------------
+
+Enable via Kconfig ``CONFIG_SYSTEM_MICROROS``:
+
+**Core Options:**
+
+- ``MICROROS_DISTRO`` — ROS 2 distribution (default: ``jazzy``)
+- ``MICROROS_TRANSPORT_UDP`` or ``MICROROS_TRANSPORT_SERIAL`` — Transport method
+
+**UDP Transport (if selected):**
+
+- ``MICROROS_AGENT_IP`` — micro-ROS agent IP (default: ``10.42.0.214``)
+- ``MICROROS_AGENT_PORT`` — Agent UDP port (default: ``8888``)
+
+**Serial Transport (if selected):**
+
+- ``MICROROS_SERIAL_DEVICE`` — Serial device path (default: ``/dev/ttyS0``)
+- ``MICROROS_SERIAL_BAUD`` — Serial baud rate (default: ``115200``)
+
+**Resource Limits:**
+
+- ``MICROROS_MAX_NODES`` — Maximum ROS nodes (default: 1)
+- ``MICROROS_MAX_PUBLISHERS`` — Publishers per node (default: 5)
+- ``MICROROS_MAX_SUBSCRIPTIONS`` — Subscriptions per node (default: 5)
+- ``MICROROS_MAX_SERVICES`` — Services per node (default: 1)
+- ``MICROROS_MAX_CLIENTS`` — Service clients per node (default: 1)
+
+Build Status
+------------
+
+Phase 2 provides configuration infrastructure. Subsequent phases will add:
+
+- Phase 3: libmicroros.a build from upstream sources
+- Phase 4: Transport layer implementations
+- Phase 5+: Examples, board support, CI integration