Bump version to 0.2.3

[aezell]

Bump the Hex package version from 0.2.2 to 0.2.3. This release includes opt-in command session identity reporting and dependency updates while retaining Elixir 1.15 / OTP 26 support. The version also sets the documentation source reference to v0.2.3.

Validation: all 72 repository tests pass on Elixir 1.18.4 / OTP 27.0.1, mix hex.build successfully builds sprites 0.2.3, and formatting passes with CI's Elixir 1.20.2 toolchain. The PR workflow checks all three supported Elixir/OTP combinations. The external SDK integration harness, which requires a separate checkout and live service credentials, was not run.

After merging, push a v0.2.3 tag on the merged commit to trigger the existing Publish to Hex workflow. Merging this PR alone does not publish the package.