⚡ Bolt: Tighten TimelineView scope in RunningView

[google-labs-jules]

💡 What: Scoped TimelineView in RunningView to only wrap CountdownRing.
🎯 Why: Wrapping static views in a SwiftUI TimelineView forces unnecessary re-evaluation on every tick, causing performance overhead.
📊 Impact: Eliminates unnecessary re-evaluations and diffing of static UI components during active session countdown.
🔬 Measurement: Verify lower CPU usage in Instruments during the active countdown state.

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PR created automatically by Jules for task 1231027323603821222 started by @TytaniumDev

[google-labs-jules]

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