Fix code style, preinstall script, and package.json files field

[Copilot]

• Fix ESLint code style errors (289 errors)
• Remove explicit eslint dependencies (provided by dotest, use npm test to lint)
• Fix preinstall.js to be optional/warning instead of throwing error
• Fix version comparison logic in preinstall.js (now correctly accepts v2.x)
• Fix package.json "files" field to include main module
• Remove spacing around square refs (obj[ref] not obj [ref])
• Remove spacing in daisy chaining (func().sub not func() .sub)
• Convert concat strings to template strings
• Update ESLint config (func-call-spacing: never, prefer-template: error)
• Code review completed
• Security scan completed (0 alerts)

Original prompt

Fix everything that is wrong or broken in this package

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[fvdm]

@copilot Syntax style: remove spacing around square refs and inside daisy chaining. And update ESLint config to require this style.

Examples:

• obj [ref] > obj[ref]
• arr [ref] [1] > arr[ref][1]
• func() .sub > func().sub

Also convert concat strings to template strings if it doesn't have a negative effect on readability or complexity.

[Copilot]

@copilot Syntax style: remove spacing around square refs and inside daisy chaining. And update ESLint config to require this style.

Examples:...

Done in commit 18ff331. Changes made:

• Removed spacing around square brackets: obj[ref], arr[ref][1]
• Removed spacing in method chaining: require().exec, text[i].trim()
• Converted string concatenations to template strings: `${bin} --version`, `v${major}.${minor}`
• Updated ESLint config: func-call-spacing: ['error', 'never'] and added prefer-template: 'error'