fix(models): coerce hex-string quantities in from_dict

[devorun]

TempoTransaction.from_dict accepts camelCase keys (chainId, maxFeePerGas, gas, value, ...), which is the Ethereum JSON-RPC convention — where quantities are hex strings (e.g. "0x64"). But it passed those values through unconverted, so parsing a standard JSON-RPC transaction dict raised TypeError: '<' not supported between instances of 'str' and 'int' during validate().

TempoTransaction.from_dict({"chainId": "0xa5bd", "gas": "0x186a0", "value": "0x64", ...})  # TypeError

This coerces quantity fields (chain_id, max_fee_per_gas, max_priority_fee_per_gas, gas_limit, nonce, nonce_key, valid_before, valid_after, and per-call value) via a small as_int helper that accepts hex strings, decimal strings, and ints. Integer and snake_case inputs are unaffected. Adds tests for both hex-string and int inputs.

[devorun]

Friendly ping on this one — it fixes a real bug: TempoTransaction.from_dict raises TypeError on JSON-RPC-style dicts with hex-string quantities (e.g. {"chainId": "0xa5bd", "value": "0x64"}), which is the standard Ethereum encoding implied by the camelCase keys it already accepts. The fix coerces the quantity fields via a small as_int helper; integer/decimal inputs are unaffected, and it adds tests for both. It's a fork PR so the Actions workflows need a maintainer to approve the run. Happy to rebase or adjust anything needed.

[devorun]

Thanks for merging #90 and #91! This one is the same class of small correctness fix — TempoTransaction.from_dict raises TypeError on JSON-RPC-style dicts with hex-string quantities (e.g. {"chainId": "0xa5bd", ...}), even though from_dict advertises camelCase/JSON-RPC keys. It's green and mergeable — would be great to land it alongside the others if it looks good. Thanks!