make compact-width iOS navigation feel iPhone-native

[austin-smith]

Problem

BitDream/Views/iOS/iOSContentView.swift:27 currently uses NavigationSplitView plus multiple toolbar menus on iPhone. That interaction model reads more like iPad/macOS than a compact-width iOS app.

Goal

Refactor the compact-width iPhone experience to use a simpler, more native navigation flow with clearer primary actions and less menu nesting.

Notes

• Current split-view structure lives in BitDream/Views/iOS/iOSContentView.swift:27.
• The toolbar currently spreads core actions across the leading menu, server menu, settings button, and bottom bar.

Acceptance Criteria

• iPhone uses a compact-width navigation structure that feels native to iOS.
• Primary actions are easier to discover and require fewer menu hops.
• The compact-width design reduces dependence on split-view affordances and overloaded toolbar menus.
• Existing torrent list, detail, refresh, search, and add flows continue to work.
• iPad and macOS behavior remain intentionally separated from the iPhone-specific solution where appropriate.