Setup workspace.package, bump up to 0.1.5

[termoshtt]

No description provided.

[Copilot]

Pull Request Overview

This PR sets up the workspace-wide package configuration and bumps the version to 0.1.5 across the repository.

• Replaces individual package metadata (version, edition, license, repository, and readme) with workspace directives.
• Updates katexit dependency versions in katexit-example and katexit-example-nightly Cargo.toml files.
• Consolidates workspace member listings and introduces a [workspace.package] section in the root Cargo.toml.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
katexit/Cargo.toml	Uses workspace directives instead of hard-coded package info.
katexit-example/Cargo.toml	Uses workspace directives and bumps dependency version.
katexit-example-nightly/Cargo.toml	Uses workspace directives and bumps dependency version.
Cargo.toml	Consolidates workspace members and defines [workspace.package].