feat: add Board Manager-based TinyStories ESP-IDF firmware

[YanKE01]

Description

This PR adds firmware/esp32_tinystories_idf, an ESP-IDF and ESP Board Manager port of the existing Arduino TinyStories firmware.

Changes

• Add a Board Manager-based ESP-IDF port for ESP32-P4, ESP32-S31, and ESP32-S3 boards, including both supported S3 LCD variants.
• Reuse the shared PLE runtime and released TinyStories model and tokenizer artifacts.

Testing

Target	Performance
ESP32-S3	10.42 tokens/s
ESP32-S31	15.80 tokens/s
ESP32-P4	20.01 tokens/s