Upgrade pyquarkchain from Python 3.8 to Python 3.13

[ping-ke]

Summary

• Upgrade all dependencies, asyncio patterns, and removed stdlib APIs to support Python 3.13
• Replace third-party jsonrpcserver/jsonrpcclient with lightweight local implementations
• All 348 tests pass cleanly

Dependencies (requirements.txt)

• jsonrpcserver / jsonrpcclient → removed (replaced with local implementations)
• aiohttp 3.1 → ≥3.9
• cryptography 2.3 → ≥42
• numpy 1.15 → ≥1.26
• websockets 8.0 → ≥12
• pytest 3.6 → ≥8, pytest-asyncio 0.9 → ≥0.23
• coincurve, ecdsa, eth-utils, eth-keys, eth-bloom, py_ecc, rlp, psutil, decorator, cachetools — all bumped to current versions
• upnpclient → async-upnp-client
• Added httpx (for the new JSON-RPC client)
• Removed pyethash and async_armor

asyncio API migration

• asyncio.get_event_loop() → asyncio.get_running_loop() or _get_or_create_event_loop() helper (depending on sync/async context) across cluster, p2p, and protocol modules
• asyncio.ensure_future() / loop.create_task() → asyncio.create_task() in synchronous methods where no running event loop is guaranteed (root_state.py, shard.py, shard_state.py, master.py)
• Removed deprecated loop= parameter from asyncio.Future, asyncio.Queue, asyncio.Event, asyncio.ensure_future, asyncio.start_server, and all connection/cancel-token classes in p2p/
• Updated asyncio.CancelledError handling (now subclass of BaseException since Python 3.9)

JSON-RPC library replacement

• Added quarkchain/cluster/jsonrpcserver.py — minimal JSON-RPC 2.0 server with method registration, dispatch, context injection, batch requests, and notification support
• Added quarkchain/jsonrpc_client.py — lightweight async JSON-RPC client using httpx
• Updated quarkchain/cluster/jsonrpc.py HTTP and WebSocket handlers to use the new dict-based dispatch API

Python 3.12+ removed APIs

• unittest.TestCase.assertRaisesRegexp → assertRaisesRegex (17 occurrences in test_shard_state.py and test_root_state.py)
• unittest.TestCase.assertDictContainsSubset → assertTrue(expected.items() <= actual.items())

p2p module

• Removed all loop= parameters from CancelToken, connections, and server classes
• asyncio.get_event_loop() → asyncio.get_running_loop() in services and utilities
• Removed stale loop parameters from NullConnection, VirtualConnection, P2PConnection, ClusterConnection

Test stability

• Added quarkchain/cluster/tests/conftest.py with autouse fixture that cancels all pending asyncio tasks after each test, preventing inter-test contamination from background tasks
• Added task cleanup in shutdown_clusters() test utility
• simple_network.py: start_server() and shutdown() made properly async

Code formatting

• Applied consistent formatting across the codebase

Test plan

• python -m pytest — 348 passed, 0 failures (217s)