Fix Wormhole fee allocation per private batch - #643

Summary

• apply the Wormhole volume fee once to each v4.3 private batch instead of once per leaf
• share the batch allocation between mining-reward claims, encrypted-send coin selection, max-sendable amounts, and proof-input validation
• remove the stale client-only 0.1 QTC batch minimum; current chain-private main has no separate exit minimum

Impact

Seven 0.50 QTC leaves now pay 3.49 QTC to the destination instead of 3.43 QTC. The required one-quantum protocol fee remains, while the extra 0.06 QTC is no longer left locked after the input nullifiers are consumed.

A single 0.50 QTC leaf still pays 0.49 QTC because the circuit and chain quantize the 4 bps fee up to one 0.01 QTC quantum for that private batch.

Validation

• repository-wide Dart formatting passed for all four packages
• focused quantus_sdk suites passed: 41 tests
• focused mobile send suites passed: 27 tests
• chain-private 7c50569c focused mining quantization test passed
• chain-private 7c50569c focused one-quantum Wormhole settlement test passed
• repository-wide fatal-info analysis was stopped at the required 10-second cap; cold-wallet, miner, and quantus_sdk completed cleanly before the cap, and the changed mobile path compiled and passed its focused tests