refactor(V2): hyperliquid client da SDK a httpx + eth-account EIP-712 (parità V1)

Riscritto interamente HyperliquidClient su httpx puro + eth-account per la
firma EIP-712 L1 (chainId 1337, phantom agent source 'a'/'b' per
mainnet/testnet). Bit-parity verificata contro hyperliquid.utils.signing
in test_signing_parity_with_canonical_sdk.

16 metodi pubblici, 26 test passanti. Aggiunte deps: eth-account, msgpack,
eth-utils. hyperliquid-python-sdk ancora presente nel pyproject; rimossa
nel sweep finale.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

uv.lock

@@ -141,9 +141,12 @@ version = "2.0.0"
 source = { editable = "." }
 dependencies = [
     { name = "alpaca-py" },
+    { name = "eth-account" },
+    { name = "eth-utils" },
     { name = "fastapi" },
     { name = "httpx" },
     { name = "hyperliquid-python-sdk" },
+    { name = "msgpack" },
     { name = "numpy" },
     { name = "pandas" },
     { name = "pybit" },
@@ -168,9 +171,12 @@ dev = [
 [package.metadata]
 requires-dist = [
     { name = "alpaca-py", specifier = ">=0.30" },
+    { name = "eth-account", specifier = ">=0.13.7" },
+    { name = "eth-utils", specifier = ">=5.3.1" },
     { name = "fastapi", specifier = ">=0.115" },
     { name = "httpx", specifier = ">=0.27" },
     { name = "hyperliquid-python-sdk", specifier = ">=0.6" },
+    { name = "msgpack", specifier = ">=1.1.2" },
     { name = "numpy", specifier = ">=1.26" },
     { name = "pandas", specifier = ">=2.2" },
     { name = "pybit", specifier = ">=5.7" },