fix: normalize tool call ids before persisting events

[Gai-shi]

HUMAN:
I verified this bugfix locally and it matches the issue reproduction scope.

---

AGENT:

Why

Parallel MCP tool calls can produce tool call IDs containing characters such as :.
Those IDs are persisted into conversation events and later used to link agent
actions with tool observations. If invalid IDs enter persisted history, replaying
the conversation through the OpenAI Responses API can fail because Responses only
accepts letters, numbers, underscores, and dashes in function call IDs.

This PR normalizes tool call IDs when SDK MessageToolCall objects are created
from LLM tool-call outputs, before those IDs are persisted into conversation events.

Summary

• Normalize Chat Completions tool call IDs before creating SDK MessageToolCall objects.
• Normalize OpenAI Responses function call call_id values when parsing Responses output.
• Add regression coverage for parallel colon-delimited tool call IDs flowing through conversation.run() into ActionEvent and ObservationEvent.

Issue Number

fixes #4578

How to Test

Ran:

UV_CACHE_DIR=.uv-cache uv run pytest tests/sdk/agent/test_tool_call_id_normalization.py tests/sdk/llm/test_message_tool_call.py -q
UV_CACHE_DIR=.uv-cache uv run pre-commit run --files openhands-sdk/openhands/sdk/llm/message.py tests/sdk/agent/test_tool_call_id_normalization.py

Results:

10 passed
pre-commit passed: ruff format, ruff lint, pycodestyle, pyright, import rules, tool registration

Video/Screenshots

N/A. This is an SDK event serialization bugfix covered by automated tests.

Design Doc

N/A. Small scoped bugfix.

Type

• Bug fix
• Feature
• Refactor
• Breaking change
• Docs / chore

Notes

This prevents newly generated colon-delimited tool call IDs from being persisted.
It does not migrate or repair already persisted historical conversations that contain
invalid tool call IDs.

[all-hands-bot]

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