[WASM] Integration tests: Decorated tools

[awsarron]

Parent issue

strands-agents/sdk-typescript#1104

Scope

Write integration tests validating Python-defined tools crossing the WASM boundary:

• @tool decorator with various type annotations (str, int, list, dict, Optional, etc.)
• @tool with Google-style docstrings for schema generation
• Tool class (manual tool definition with name, description, schema, invoke callback)
• PydanticTool (Pydantic model-based tool definition)
• Tool invocation via natural language (model decides to call)
• Direct tool invocation via agent.tool.tool_name(param=value)
• Multi-tool invocation (model calls multiple tools in one turn)
• Tool error handling (exceptions in Python tool code)

Context

This tests the host→guest tool-provider import boundary. When the TS SDK agent loop needs to call a tool, it crosses back into Python via the WIT call-tool import. Results flow back as tool-event-stream resources.

Key areas of concern:

• Type serialization/deserialization across the boundary
• Error propagation from Python → WASM guest
• Stream events for tool execution (tool_use, tool_result)

Done when

• @tool decorator works with common Python types
• Tool class works for manual definitions
• PydanticTool works for Pydantic model-based tools
• Direct method call (agent.tool.name()) works
• Multi-tool calls in a single turn work
• Tool errors propagate cleanly without crashing the WASM instance