[RFC] sim: implement proper Firehose protocol state machine

[igoropaniuk]

Replace the stub sim_read()/sim_write() with a simulator that parses incoming XML commands and enqueues matching XML responses, mirroring the real Firehose device protocol. This decreases divergence in behavior between the real HW and the dry-run mode, giving better validation of the flashing process in dry-run mode.

sim_write() now dispatches based on the command tag:

• configure: enqueue log + ACK echoing the same max payload size so firehose_try_configure() does not trigger a redundant exchange
• program/read: enqueue log + rawmode=true ACK and transition to SIM_STATE_RAW_IN/RAW_OUT to track the raw binary transfer
• erase/patch/setbootablestoragedrive/ufs: enqueue log + ACK
• power: enqueue log + ACK and mark the simulator as closed

sim_read() first drains the XML response queue (ensuring protocol responses are delivered before any raw data), then serves zero-filled sector data in SIM_STATE_RAW_OUT, and returns -EIO once closed so the trailing drain in firehose_reset() completes immediately.

Since the simulator now produces correct protocol responses, remove the QDL_DEVICE_SIM early-return guards in firehose_read() and firehose_try_configure() that previously bypassed response parsing.

Pre-initialize qdl->sector_size = 4096 in sim_init() and only probe sector size in firehose_try_configure() if unset. Previously, the probe commands were executed during --createdigest dry-runs and included in the VIP digest table, but not issued during real VIP flashing (where probing is gated on VIP_DISABLED). This caused all subsequent digest entries to shift, resulting in hash mismatches on the device.

[lumag]

LGTM!

[igoropaniuk]

Friendly ping 🙂 Please let me know if there are any additional concerns or comments. If everything looks good, this might be ready to land.