Fix ESP32-S2 firmware build errors

[Copilot]

Four -Werror compilation failures in the ESP-IDF firmware build.

Changes

• src/main.cpp — Remove invalid capture of static local transport in the SetRxCallback lambda.
• src/main.cpp — Add #include "esp_efuse_table.h" to bring ESP_EFUSE_OPTIONAL_UNIQUE_ID into scope.
• src/web/web_server.cpp — Explicitly initialize all seven httpd_uri_t fields in every URI entry to silence -Werror=missing-field-initializers.
• lib/libcanard/canard_pio.c (new) — PlatformIO/ESP-IDF wrapper for canard.c that pre-includes <stdlib.h> with _GNU_SOURCE and _BSD_SOURCE suppressed. This prevents Espressif's picolibc from declaring long int random(void), which conflicts with libcanard's internal static uint64_t random(canard_t*, uint64_t) (ESP-IDF's assert.h unconditionally includes stdlib.h, surfacing the conflict).
• lib/libcanard/library.json (new) — Compiles only canard_pio.c via srcFilter, uses -std=c11 to avoid the C23 stdbit.h requirement absent from the Xtensa toolchain, and -Wno-error to suppress the ESP-IDF toolchain's -fuse-cxa-atexit (a C++-only flag incorrectly present in the shared cflags response file).
• lib/o1heap/library.json (new) — Same -std=c11 and -Wno-error flags to fix the identical -fuse-cxa-atexit issue for o1heap.

[Tecnologic]

@copilot build still fails

[Copilot]

@copilot build still fails

The root cause was GCC's -Wmissing-field-initializers warning fires even with designated initializers when trailing struct fields are omitted. Fixed in d9324ba by explicitly specifying all httpd_uri_t fields (.is_websocket, .handle_ws_control_frames, .supported_subprotocol) in every URI entry so no field is left uninitialized.

[Tecnologic]

@copilot fix build errors and verify that pipeline is green

[Copilot]

@copilot fix build errors and verify that pipeline is green

Both pipelines are now green on commit 54e6470. Here's a summary of all fixes applied:

1. web_server.cpp — explicitly initialize all httpd_uri_t fields to silence -Wmissing-field-initializers
2. lib/libcanard/canard_pio.c — new PlatformIO wrapper that pre-includes <stdlib.h> with _GNU_SOURCE/_BSD_SOURCE suppressed; this prevents picolibc from declaring long int random(void), which conflicts with canard's internal static uint64_t random(...) function (ESP-IDF's assert.h unconditionally includes stdlib.h, surfacing the conflict)
3. lib/libcanard/library.json — srcFilter to compile only canard_pio.c, -std=c11 to avoid the C23 stdbit.h requirement, -Wno-error to suppress the ESP-IDF toolchain's -fuse-cxa-atexit (a C++-only flag incorrectly present in the shared cflags response file)
4. lib/o1heap/library.json — same -std=c11 and -Wno-error for the -fuse-cxa-atexit issue