docs: point World CLI users to world-engine

[smsunarto]

World CLI now ships inside the world-engine module (Argus-Labs/world-engine#1023), so a game's CLI always matches its World Engine version. This repo no longer gets releases, and the install.world.dev scripts are deprecated.

The README now shows go install github.com/argus-labs/world-engine/cli/cmd/world@latest, plus the go mod edit -tool flow for existing games. Past release binaries stay available.

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Summary by cubic

Deprecates the world-cli repository and points users to World CLI, which now ships inside world-engine so a game's CLI always matches its World Engine version.

• The README now directs users to install via go install github.com/argus-labs/world-engine/cli/cmd/world@latest and use the go mod edit -tool flow for existing games.
• This repo no longer receives releases, and the install.world.dev scripts are deprecated; requires Go 1.27.1 or later.
• Binaries from past releases remain available for projects pinned to them.

^{Written for commit c6def1b. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}

[codecov]

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