remove downloads storyboard and other minor clean up

[brindy]

Task/Issue URL: https://app.asana.com/1/137249556945/project/1200194497630846/task/1213916260872783?focus=true
Tech Design URL:
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Description

Remove downloads storyboard.

Testing Steps

1. Run the app and check downloads screen opens.
2. Download a file make sure it appears in downloads
3. Delete the file, make sure downloads updates

Impact and Risks

Low: Minor visual changes, small bug fixes, improvement to existing features

What could go wrong?

Quality Considerations

Notes to Reviewer

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Internal references:

Definition of Done | Engineering Expectations | Tech Design Template

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Note

Medium Risk
Mostly a UI navigation refactor, but it also upgrades content-scope-scripts to a new major version which could affect content blocking behavior at runtime.

Overview
Removes Downloads.storyboard from the project and updates segueToDownloads() to present DownloadsListHostingController() directly instead of instantiating a storyboard.

Updates DownloadsListHostingController to be initializer-driven (no init(coder:) support) and performs minor appearance setup cleanup. Separately bumps the SwiftPM content-scope-scripts dependency from 13.41.0 to 14.0.0 in Package.resolved.

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