[CI] Fix nightly build failures (#2257)

- Convert nightly workflow to matrix builds to fix FRAMEWORK_DIR issues
  caused by platform_packages conflicts when building sequentially
- Each environment now builds on its own runner, matching build.yml
- Add deploy job that collects all artifacts and deploys docs
- Add extra_scripts to esp32dev-pilight environment to fix implicit
  function declaration error with newer GCC toolchain

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Florian <1technophile@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

environments.ini

@@ -286,6 +286,7 @@ custom_description = RF gateway using RCSwitch library
 [env:esp32dev-pilight]
 platform = ${com.esp32_platform}
 platform_packages = ${com.esp32_platform_packages}
+extra_scripts = pre:scripts/add_c_flags.py
 board = esp32dev
 board_build.partitions = min_spiffs.csv
 lib_deps =