Bump version to 1.0.3

[hemanth-asirvatham]

Motivation

• Prepare a new release by updating the project metadata and package version to 1.0.3.

Description

• Update version in pyproject.toml to 1.0.3 and set __version__ in src/gabriel/_version.py to 1.0.3.

Testing

• No automated tests were run for this metadata-only change.

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Codex Task

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