⚡ Bolt: Cache Foundation formatters to improve UI and scanning performance

[acebytes]

💡 What
Created a centralized Formatters enum to lazily initialize and store shared instances of ByteCountFormatter and ISO8601DateFormatter. Replaced all repetitive ad-hoc instantiations across the codebase with references to these shared instances.

🎯 Why
Instantiating Foundation formatters (DateFormatter, ISO8601DateFormatter, ByteCountFormatter) is a known, computationally expensive operation in Swift. Repeatedly instantiating them inside rendering loops (like SwiftUI views or list builders) and high-frequency scan parsing methods introduces unnecessary allocation overhead, impacting smooth scrolling and the execution time of cache scanning.

📊 Impact

• Eliminates repeated memory allocations for formatters across standard UI components, CLI rendering, and backend JSON tagging.
• Accelerates the UI update cycle by reusing formatters for the scanResults list and Quick Stats indicators.
• Removes garbage collection/ARC overhead for short-lived formatters during batch processing operations.

🔬 Measurement
Verify the changes by compiling the application and observing UI performance on the CleanConfirmation modal and main CacheoutViewModel results page. Ensure the reported sizes match expected formatting. Running cacheout --cli scan will also exhibit fractionally faster parsing/output due to reused formatting during disk sweeps.

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PR created automatically by Jules for task 16235758208118321414 started by @acebytes

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid sharing non-Sendable formatter singletons

The new Formatters globals introduce shared ByteCountFormatter/ISO8601DateFormatter instances that are accessed from different isolation domains (for example @MainActor view-model formatting and CacheCleaner actor logging). Both formatter classes are mutable and non-Sendable, so this pattern creates cross-actor shared state that can race at runtime and is flagged by Swift concurrency diagnostics (MutableGlobalVariable, which becomes an error in Swift 6 mode). Prefer actor-local formatters or isolate these globals to a single global actor.

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