Support Bitcrane RP2040 bridge control quirks

[benjamin-wilson]

Summary

This PR makes the s19jpro-bitcranev3 path work against the current Bitcrane v3 RP2040 bridge firmware and improves runtime visibility for the S19j Pro bring-up.

It includes:

• USB identity compatibility for the flashed OSMU/bitcrane3 device
• tolerance for the bridge firmware's legacy malformed control-error frames
• API exposure for S19j Pro frequency, APW12 voltage, hashboard count, active hashboard count, per-hashboard state, per-hashboard hashrate, and aggregate miner hashrate
• real nonce-derived hashrate reporting instead of static estimates
• non-blocking scheduler source-command handling so share submission backpressure cannot wedge the scheduler
• serialized BM13xx cold-start initialization across S19j Pro hashboards so bring-up stays reliable while the scheduler remains responsive

Why

Before these changes, Mujina could detect the Bitcrane board but was not reliable end-to-end with the currently flashed RP2040 firmware:

• the board identity did not match the branch's USB matcher
• legacy bridge control responses could break management traffic
• share submission could stall the scheduler under load
• making thread assignment asynchronous exposed shared-PSU/shared-control contention during simultaneous three-board cold-start
• S19j Pro monitoring did not expose the values needed to confirm which hashboards were really active

Validation

Validated locally against a connected Bitcrane v3 / S19j Pro setup.

Code-level validation:

• cargo check -p mujina-miner
• cargo test -p mujina-miner mgmt_protocol::bitaxe_raw::
• cargo test -p mujina-miner api::server::tests::
• cargo test -p mujina-miner asic::bm13xx::thread_v2::tests:: -- --nocapture
• cargo test -p mujina-miner scheduler::tests::
• cargo test -p mujina-miner job_source::stratum_v1::tests::

Live validation:

• board registration through the Bitcrane RP2040 bridge
• APW12 PSU control and telemetry
• three-hashboard detection and staged bring-up
• accepted pool-share submission to public-pool.io:3333
• live API reporting with real per-hashboard and aggregate hashrate
• PID fan control keeping board temperatures below 70 C during bring-up and mining

Representative live state after the fix:

• 3/3 hashboards active
• aggregate hashrate around 70.57 TH/s
• submitted shares increasing
• temperatures roughly 39 C to 49 C during steady operation