chore(timestamp): python sample A2A 1.0.3 update

[Iwaniukooo11]

Refactor: Update timestamp extension to a2a-sdk v1.0.3 and migrate to pip

Overview

This PR refactors the timestamp extension sample to align it with the stable a2a-sdk v1.0.3 API specification, improves internal naming conventions for better readability, and transitions the project's dependency management from uv to standard pip and requirements.txt.

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Key Changes

1. Project Layout Re-organization

• Standard Package Structure: Re-structured the extension layout to follow standard Python packaging best practices:
  • Moved all core source files into a dedicated src/timestamp_ext/ package (containing client.py, core.py, and server.py).
  • Consolidated and migrated test files into the tests/ directory (containing __main__.py and test_client.py).

2. Upgrade to a2a-sdk v1.0.3 Stable API

• Facade Imports: Migrated all legacy internal protobuf import paths (e.g., a2a.types.a2a_pb2 and a2a.helpers.proto_helpers) to the clean, stable a2a.types and a2a.helpers facades across all source and test files.
• String Bindings: Replaced the deprecated TransportProtocol.JSONRPC enum references with standard string literals ('JSONRPC') directly in AgentInterface setup.
• Dependency Bump: Updated pyproject.toml version constraint to target a2a-sdk>=1.0.3.

3. Dependency Management Transition (uv $\rightarrow$ pip)

• Auto-compiled requirements.txt: Generated a fully resolved and pinned requirements.txt from pyproject.toml using uv pip compile to support standard pip install environments.
• Lockfile Cleanup: Safely removed the legacy uv.lock file.

4. Readability & Explicit Naming

• Self-Documenting Delegates: Renamed all generic delegate variables, parameters, and fields to highly explicit, self-documenting names for better architecture visibility:
  • delegate $\rightarrow$ delegate_client (in _TimestampingClient)
  • delegate $\rightarrow$ delegate_client_factory (in _TimestampingClientFactory)
  • delegate $\rightarrow$ delegate_agent_executor (in _TimestampingAgentExecutor)
  • delegate $\rightarrow$ delegate_event_queue (in _TimestampingEventQueue)

[gemini-code-assist]

Code Review

This pull request restructures the Python Timestamp Extension showcase by modularizing the codebase into separate core, client, and server modules, updating the documentation, and adding integration tests. The review feedback identifies several critical issues: Python 3.10 compatibility is broken by using datetime.UTC instead of datetime.timezone.utc in both the core logic and tests; the integration tests risk hanging indefinitely due to unread subprocess pipes and a lack of timeout during process termination; and the README contains a documentation error where ClientFactory is instantiated with an incorrect parameter name.

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