Tooling: Use correct var name and tweak output in jetpack watch

[tbradsha]

Proposed changes:

This updates an typo per a PR review (https://github.com/Automattic/jetpack/pull/46686/changes#r2716347873): packageJson → composerJson

It also tweaks the output:

$ jetpack watch plugins/jetpack
Watching 'plugins/jetpack'...
Go write some code.

There should not be any function change.

Other information:

• Have you written new tests for your changes, if applicable?
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Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

Run jetpack watch plugins/jetpack and see the new output.

Changelog

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[Copilot]

Pull request overview

This PR updates the jetpack watch CLI command implementation to use the correct variable name for parsed composer.json data and adjusts the user-facing console output when watch mode starts.

Changes:

• Rename the watch() function parameter from packageJson to composerJson for correctness/consistency with readComposerJson.
• Update jetpack watch startup message to the new, simpler wording.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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[Copilot]

hasWatchStep() currently returns a boolean, but the local variable is named command and checked via command === false, which is misleading. Consider renaming it to something like hasWatch/hasWatchScript and using a direct boolean check to make the intent clearer.

Suggested change

	const command = hasWatchStep( project, composerJson, hot );
	if ( command === false ) {
	const hasWatch = hasWatchStep( project, composerJson, hot );
	if ( ! hasWatch ) {

[anomiex]

Seems ok. Didn't test.