feat(core): comprehensive bittensor-rs refactor with full Python SDK parity

[echobt]

Summary

This major refactor brings bittensor-rs to feature parity with the Python bittensor SDK (opentensor/bittensor).

Changes

New Modules

• Wallet: Complete wallet management with keyfile encryption, mnemonic support, keypair generation, and path traversal protection
• Axon: HTTP server module for receiving Dendrite requests with middleware support
• Dendrite: HTTP client module for communicating with Axon servers
• CLI (btcli): Command-line interface for network operations
• Logging: Comprehensive logging system with multiple output formats

Enhanced Features

• Synapse System: SynapseType trait, body hash computation, streaming support
• Queries: Hyperparameters, associated IPs, commitment queries
• Governance: Senate operations and proxy account management
• Error Handling: Comprehensive typed errors for all SDK operations

Code Quality

• SCALE decoding properly integrated (no hardcoding)
• Security hardening for keyfile handling and encryption
• Full clippy compliance with no warnings
• Proper error handling throughout

Testing

• cargo check passes
• All existing tests pass

Stats

• 49 files changed
• 17,320 insertions(+), 108 deletions(-)