ESP32C6: Board Skeleton Creation

[alieissa-commits]

Goal: Set up the project structure and integrate Espressif's esp_timer using ThreadX.

Deliver:

• SampleX/Espressif/ESP32-C6 following the existing SampleX board layout.
• Updated SampleX, ThreadX, and NetX Duo submodule revisions.
• A pinned ESP-IDF acquisition mechanism.
• CMake/Ninja build, image generation, build/deploy scripts, README, and notice.
• Reuse of the basic ThreadX ESP32-C6 example support through libs/threadx.
• Pinned timer-source manifest and reproducible adaptation patch application.
• Shared SYSTIMER ownership with counter 1/alarm 0 for the ThreadX tick and counter 0/alarm 2 for the high-resolution timer.
• ThreadX-adapted IDF timer thread, event notification, interrupt backend, allocator, esp_timer_get_time(), and ETS compatibility API.

Exit criterion: the SampleX starter boots, runs ThreadX, and passes the same basic kernel validation as the ThreadX example without carrying a fork of the generic RV32 port. High-resolution one-shot, periodic, cancellation, rearm, and deferred deletion tests pass concurrently with the 100 Hz ThreadX tick.