Brand the project as CineThread

[cyou1314]

What changed

• Brand the public product as CineThread.
• Update the README, workflow documentation, roadmap, changelog, package summary, and public API/CLI descriptions.
• Point the CI badge at the future cyou1314/cinethread repository URL.

Compatibility

The Python distribution name, CLI command, package import path, and versioned JSON contract identifiers remain aigc-director-kit. This is a public-brand upgrade, not a breaking technical rename.

Validation

• 30 unittest cases passed.
• Editable installation remains version 0.2.0 and exposes the CineThread package summary.
• Source/tests compile, public JSON and schemas parse, and git diff --check passed.

Follow-up after merge

Rename the GitHub repository to cinethread, then create the existing v0.2.0 tag and GitHub Release.