feat(tck): implement createContract JSON-RPC method

[exploreriii]

Fixes #2594

Implements the createContract JSON-RPC method: CreateContractParams, handler wrapping ContractCreateTransaction (setter order matching the JS TCK server), CreateContractResponse, and a shared decode_hex util (0x-tolerant, strict) that the upcoming contract-service methods will reuse.

TCK results (local solo, TCK v0.12.0): 114 passing, 0 failing, 7 pending on the ContractCreateTransaction suite. All pendings are known-unimplemented methods tracked separately: appendFile (#2493), deleteFile (#2492).

BREAKING CHANGES: ContractCreateTransaction no longer pre-validates client-side:

• Missing bytecode source / gas now surfaces as the network's CONTRACT_BYTECODE_EMPTY / INSUFFICIENT_GAS instead of a local ValueError — the TCK spec explicitly tests for the network responses, and sibling SDKs behave this way. The network would not have let these pass anyway.
• set_gas() now raises ValueError on negative gas (JS SDK parity; required by the TCK driver's negative-gas tests, and a negative gas could never succeed on-network).
• set_bytecode_file_id() now clears bytecode (and vice versa), keeping the protobuf initcodeSource oneof consistent instead of letting kwarg order silently decide.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@           Coverage Diff           @@
##             main    #2611   +/-   ##
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  Coverage   95.44%   95.44%           
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  Files         165      165           
  Lines       10562    10567    +5     
=======================================
+ Hits        10081    10086    +5     
  Misses        481      481           

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Review configuration:

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

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Run ID: 66eea751-5022-4ebf-9b80-060b7647d908

📥 Commits

Reviewing files that changed from the base of the PR and between ac8e5b4 and 53dd86c.

📒 Files selected for processing (5)

• src/hiero_sdk_python/contract/contract_create_transaction.py
• tck/handlers/contract.py
• tck/util/param_utils.py
• tests/tck/contract_handler_test.py
• tests/unit/contract_create_transaction_test.py

Walkthrough

The PR adds the createContract JSON-RPC method, its parameter and response models, hexadecimal decoding, handler registration, and unit tests. It also changes SDK contract creation to defer missing bytecode and gas validation to the network.

Changes

Contract creation

Layer / File(s)	Summary
SDK contract creation behavior src/hiero_sdk_python/contract/contract_create_transaction.py, tests/unit/contract_create_transaction_test.py	The SDK rejects negative gas, clears alternate bytecode sources, and permits missing bytecode or gas during protobuf construction.
TCK parameters and transaction mapping tck/param/contract.py, tck/util/param_utils.py, tck/response/contract.py, tck/handlers/contract.py	The TCK adds contract creation models, hexadecimal decoding, contract field mapping, and bytecode-source precedence.
RPC registration and execution tck/handlers/__init__.py, tck/handlers/contract.py, tests/tck/contract_handler_test.py	The handler is registered, executes the transaction, validates the receipt, returns the contract ID and status, and is covered by unit tests.

Estimated code review effort: 3 (Moderate) | ~30 minutes

Merge Risk: 🔵 Low · up to ac8e5

The PR adds the createContract method and changes contract-creation validation and oneof handling. It is mergeable with explicit owner follow-up because negative constructor gas, whitespace in hexadecimal input, and conflicting staking IDs can produce inconsistent validation or request behavior.

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant create_contract
  participant CreateContractParams
  participant ContractCreateTransaction
  participant Network
  Client->>create_contract: createContract request
  create_contract->>CreateContractParams: parse JSON parameters
  create_contract->>ContractCreateTransaction: apply contract fields
  create_contract->>Network: execute transaction
  Network-->>create_contract: receipt with contract ID and status
  create_contract-->>Client: CreateContractResponse

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 48.48% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 33 functions across 8 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the primary change: implementing the TCK createContract JSON-RPC method.
Description check	✅ Passed	The description directly explains the createContract implementation, related transaction behavior changes, tests, and TCK results.
Linked Issues check	✅ Passed	The changes satisfy issue #2594. They add and register createContract, define request and response models, support inline and file-based bytecode, decode hexadecimal values, apply transaction paramete…
Out of Scope Changes check	✅ Passed	The transaction validation updates, handler registration, parameter and response models, utility, and tests all support the linked issue objectives. No unrelated code changes are identified.

Full details: Linked Issues check

Explanation

The changes satisfy issue #2594. They add and register createContract, define request and response models, support inline and file-based bytecode, decode hexadecimal values, apply transaction parameters, validate responses, and add tests. The described TCK suite results also support compliance. The excluded uv.lock file is not required for the issue objectives.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 4

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 443000ae-e8ae-478c-9b1d-84d2bd6d12bc

📥 Commits

Reviewing files that changed from the base of the PR and between e8ed509 and ac8e5b4.

⛔ Files ignored due to path filters (1)

• uv.lock is excluded by !**/*.lock

📒 Files selected for processing (8)

• src/hiero_sdk_python/contract/contract_create_transaction.py
• tck/handlers/__init__.py
• tck/handlers/contract.py
• tck/param/contract.py
• tck/response/contract.py
• tck/util/param_utils.py
• tests/tck/contract_handler_test.py
• tests/unit/contract_create_transaction_test.py

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[aceppaluni]

Two thing from me:

Were the changes in uv.lock intentional?

[manishdait]

should we move this check to the sdk's CreateContractTransaction class. to handle this within the sdk by rasing OverflowError. Similar to the Uint256 datatype field in AccountCreateTransaction