Implement or remove documented L5 performance APIs that do not exist

[schatt]

Summary

High-quality / 100% coverage cannot include advertised APIs that do not exist. Docs and examples call L5 performance modifiers that have zero func in Framework/Sources.

Spawned from #402: orphan L5 tests compiled against these names and would not have compiled if wired.

Documented but missing

Framework/docs/README_Layer5_Performance.md points at Shared/Views/Extensions/PlatformPerformanceExtensionsLayer5.swift — that file is not in the tree.

Called from docs / examples (non-exhaustive; grep platformMemoryOptimization in Framework/docs/):

• platformMemoryOptimization()
• platformRenderingOptimization()
• platformViewCaching()
• platformAnimationOptimization()
• platformCachingOptimization()
• platformLazyLoading() / platformLazyLoading { }
• platformPerformanceOptimized(for:)
• platformMemoryOptimized(for:)

Related phantom types from the deleted orphan suite (also not in Sources): MemoryConfig, LazyLoadingConfig, ViewPerformanceMetrics, PerformanceOptimizationLevel, PerformanceCachingStrategy, PerformanceRenderingStrategy.

Choose one (do not leave docs lying)

1. Implement the modifiers (and any types) in Framework/Sources, then TDD real contracts in executing SixLayerFrameworkUnitTests, or
2. Remove them from docs/examples (README_Layer5_Performance.md, DeveloperExtensionGuide.md, ExtensionQuickReference.md, CustomViewsAndBusinessLogicGuide.md, README_UsageExamples.md, AI_AGENT_*.md, etc.).

Partial implement + leftover doc references is a fail for this issue.

Out of scope

• Tests for APIs that already exist in PlatformIOSOptimizationsLayer5.swift / PlatformMacOSOptimizationsLayer5.swift → Add executing tests for platformIOSHapticFeedback (L5 iOS) #423, Cover remaining PlatformIOSOptimizationsLayer5 APIs (L5 iOS) #424, Real tests for MacOSOptimizationManager host-resource strategy #422.

References

• Wire or remove orphan LayeredTestingSuite (not in any XcodeGen target) #402
• Docs: Framework/docs/README_Layer5_Performance.md

[schatt]

Parent tracker: #426. Existing L5 source coverage: #422 #423 #424.