Add end-to-end deploy, compile, and flash workflow

[katzworld]

Summary\n- add deploy.py to run prepare/train/export/assets/host-verify in one flow\n- add flash.py to optionally run full pipeline, compile with standalone Arduino CLI, auto-detect USB port, upload sketch, and flash model partition\n- add serial command support in firmware to continue generation and reset/change prompt IDs at runtime\n- update README docs for start-to-finish workflow\n\n## Validation\n- python3 -m py_compile deploy.py flash.py\n- flash.py --help shows new full-pipeline options\n- firmware compile/upload verified on ESP32-S3 with esp32 core 3.3.10\n

[katzworld]

Working stage update (local-tested -> pushed)

This push syncs the latest firmware behavior that was validated on hardware:

1. Continuous autonomous storytelling mode (no serial command interaction needed).
2. Clean serial output: story text only (throughput/telemetry lines removed).
3. Automatic context rollover so generation continues without Enter/input.
4. Startup diversity improvements: randomized seed prompt bank + stochastic sampling with repeat penalty.

Usage:

uv run python flash.py --skip-model
stty -F /dev/ttyACM0 115200 raw -echo
cat /dev/ttyACM0

Example output:

the cat and wanted to go outside.
"Look, I found something big!" the little cat hopped towards it and found some flowers.
Then, a mean dog came running down the stairs to the park.
The dog jumped on a leaf and chased it with its nose.

Note: timeout ... cat returning exit code 124 is expected when timeout expires.