[SYS] esp32_platform: update to 55.03.39 (#2329)

* esp32_platform: update to 55.03.39

## Summary

- Add support for Python 3.14
- Improve ESP32 platform and framework compatibility.
- Update board support and toolchain integrations.
- Fix stability and hardware-specific issues across supported ESP32 targets.
- Release notes:
    - [55.03.39](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.39)
    - [55.03.38](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.38)
    - [55.03.37](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.37)
    - [55.03.36](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.36)
    - [55.03.35](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.35)
    - [55.03.34](https://github.com/pioarduino/platform-espressif32/releases/tag/55.03.34)

* update build to use python 3.14 with platformio 6.1.19

* Update esp32-arduino-lib-builder to v1.5

* [CI] Fix call8 link overflow on large Xtensa builds (IDF 5.5.4)

The 55.03.39 / IDF 5.5.4 bump enlarges the precompiled libs enough that
large Xtensa images (esp32 / esp32s3) overflow the call8 reach and fail to
link with "dangerous relocation: call8: call target out of range".
-mlongcalls (which makes calls linker-relaxable) is injected by
esp32-arduino-libs into the framework compile but NOT into lib_deps
(NimBLE-Arduino, ArduinoJson) or project sources.

Add a project pre: extra_script (scripts/add_mlongcalls.py) that applies
-mlongcalls to CCFLAGS/ASFLAGS, gated on the Xtensa MCUs (RISC-V c3 has no
call8 and rejects the flag). Wired into [env]; the four esp32dev-*pilight*
envs that set their own extra_scripts list it explicitly too, since
PlatformIO replaces rather than merges extra_scripts.

Also bump esp32-arduino-libs 0.1.5 -> 0.1.6, which restores the
framework-side -mdisable-hardware-atomics / -fno-builtin-* flags that 0.1.5
dropped under IDF 5.5.4 (separate from the lib_deps call8 issue).

Verified clean (0 call8): esp32dev-all-test, esp32dev-ble, theengs-bridge,
theengs-plug, esp32dev-pilight (+cc1101); esp32c3 unaffected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Florian <florian@theengs.io>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/README.md

@@ -472,7 +472,7 @@ prepare → build (task-build.yml) → deploy → documentation (task-docs.yml)
 
 **Parameters**:
 - `python-version`: Python version to use (default: '3.13')
-- `pio-version`: PlatformIO version to use (default: 'v6.1.18')
+- `pio-version`: PlatformIO version to use (default: 'v6.1.19')
 - `environment-set`: Which set of environments to build: 'all' or 'ci' (default: 'all')
 - `enable-dev-ota`: Enable development OTA builds (default: false)
 - `version-tag`: Optional version tag to pass to ci.sh build - omitted if empty (default: '')
@@ -501,7 +501,7 @@ prepare → build (task-build.yml) → deploy → documentation (task-docs.yml)
 
 **Technical Details**:
 - Runs on: Ubuntu latest
-- PlatformIO version: Configurable via `pio-version` input (default: v6.1.18, custom fork: `pioarduino/platformio-core`)
+- PlatformIO version: Configurable via `pio-version` input (default: v6.1.19, custom fork: `pioarduino/platformio-core`)
 - Python package manager: `uv` (astral-sh/setup-uv@v6)
 - Environment sets: `all` (complete set) or `ci` (subset for quick validation)
 - Strategy: Matrix with fail-fast: false (builds complete even if one environment fails)
@@ -743,7 +743,7 @@ All build environments are defined in `.github/workflows/environments.json`:
 - Provides consistent CLI across all operations
 
 **Build System** (`ci.sh build`):
-- PlatformIO 6.1.18 from custom fork: `pioarduino/platformio-core`
+- PlatformIO 6.1.19 from custom fork: `pioarduino/platformio-core`
 - Python package manager: `uv` for fast dependency installation
 - Orchestrator: `ci_build.sh`
   - Worker: `ci_build_firmware.sh` (PlatformIO compilation)