Three fixes:
- Add .cargo/config.toml with -Tlinkall.x for xtensa target (resolves
ROM functions, interrupt handlers, memory layout)
- Add integrated-timers feature to embassy-executor for ESP32 boards
(resolves _embassy_time_schedule_wake)
- Add `use esp_println as _` to pull in defmt global_logger (was being
stripped as dead code because nothing referenced the crate)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
