Add Download Step

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Coverage after merging download into main

91.55%

Coverage Report

File	Stmts	Funcs	Lines	Uncovered Lines
/Users/runner/work/SwiftScraper/SwiftScraper/Sources/SwiftScraper
Browser.swift	75%	65.38%	76.51%	130–138, 142, 163–164, 173–184, 197–198, 210–211, 235–236, 72, 79
JavaScriptGenerator.swift	100%	100%	100%
StepRunner.swift	95.73%	90.91%	96.23%	134, 173–175
SwiftScraperError.swift	100%	100%	100%
/Users/runner/work/SwiftScraper/SwiftScraper/Sources/SwiftScraper/Steps
AsyncProcessStep.swift	100%	100%	100%
AsyncScriptStep.swift	100%	100%	100%
DownloadStep.swift	87.80%	83.33%	88.57%	67, 71–73
OpenPageStep.swift	96.55%	100%	96.15%	28
PageChangeStep.swift	92.68%	80%	94.44%	48
ProcessStep.swift	100%	100%	100%
ScriptStep.swift	98.04%	100%	97.78%	61
WaitForConditionStep.swift	95.92%	90%	96.59%	53, 58
WaitStep.swift	100%	100%	100%
/Users/runner/work/SwiftScraper/SwiftScraper/Sources/SwiftScraper/Steps/Common
NavigableStep.swift	100%	100%	100%
StepCompletionCallback.swift	100%	100%	100%
StepFlowResult.swift	100%	100%	100%