Update apple-platform-dev skill with Phase 4 Alpha guidance

[kj6dev]

Overview

Update the apple-platform-dev skill and CLAUDE-SWIFT.md with coding conventions identified during Phase 4 Alpha preference discovery sessions.

High Priority Updates

Type Inference Guidelines

• Prefer type inference
• Use explicit types for: type coercion (let padding: CGFloat = 16.0) and static member shorthand (let token: SpaceToken = .x4)

Action Handler Naming

• Direct actions: *Action suffix (saveAction)
• Event handlers: on* prefix (onSheetDismissed)

Boolean Property Naming

• Preferred: is prefix (isLoading, isEnabled)
• Acceptable: has prefix (hasError)
• Avoid: shows, displays

View Suffix Conventions

• View: General SwiftUI components
• Row: List/ForEach items
• Page: Full-screen views

Medium Priority Updates

• Constants Enum Organization: Prefer flat enum Constants, split if large
• Common Value Extraction Threshold: Extract when 2+ uses AND meaningful cleanup
• Computed Property Naming: Noun form (header), avoid verb form (buildHeader)
• Preview Organization: Multiple for data states, single if variations not revealing

Low Priority Updates

• No leading underscores in property names
• Protocol conformance placement guidelines
• Nested types guidelines
• Preview content strategy
• Preview naming conventions
• Binding naming conventions

Already Implemented

• EmptyView Anti-Pattern → CLAUDE-SWIFT.md
• ViewModel Naming Standard → CLAUDE-SWIFT.md
• Property Wrapper Line Breaks → apple-platform-dev skill
• Pointless Container Anti-Pattern → apple-platform-dev skill
• View Extraction Decision Matrix → apple-platform-dev skill
• Extension Usage Guidelines → apple-platform-dev skill
• Extension File Naming → apple-platform-dev skill

Reference

Full session archive: PreferenceDiscovery/archive/phase4-alpha/