fix: harden fairyringclient for mainnet validator use

[ap0calypse644]

Summary

• add configurable gas price and include non-zero fees in every signed transaction
• validate fee denom, gas price, and 32-byte Cosmos private keys
• serialize queued transactions through commit to prevent account-sequence races
• fail immediately on sync broadcast CheckTx rejection instead of waiting forever for an uncommitted tx
• keep private/general keyshare handling active while blockwise keyshare submission remains disabled
• process multiple general-keyshare request events from the same block
• remove raw current/pending/derived keyshare material from logs
• update delegate transactions to use the configured fee settings
• correct the embedded client version string to v1.0.1
• add config/fee regression tests and PR CI

Mainnet rationale

Fairyring mainnet validators enforce minimum-gas-prices = 0.025ufair. The existing v1.0.1 client set gas limits but signed fee-less transactions, so general/private keyshare submissions would be rejected by CheckTx.

For the mainnet validator deployment, standalone fairyringclient is responsible for private/general keyshares only. SubmitBlockwiseKeyshares remains false; blockwise keyshares are handled by fairyringd vote extensions.

Security / reliability

The previous client logged derived and cached keyshare values. These logs are removed. The previous tx queue launched each item in a goroutine; it now processes each transaction serially through commit so the next transaction observes the incremented account sequence.