[2/3] Interactive Compose previews: enable component snippets - #1191

⚡ Jetpack Compose Performance Review

No Jetpack Compose performance issues were found in the changed code.

Summary of Audit

• Strict Diff Scope: All newly introduced and modified lines (+ lines) across the 21 touched files in .gemini/pr_diff.patch were evaluated against Categories 1–7 of the Jetpack Compose Performance guidelines.
• Icon Rendering & Allocations: The introduction of AppIcons lazily caches all parsed ImageVector instances (by lazy) at the singleton object level, avoiding repeated SVG path parsing or runtime decoding during composition passes. Uses of Icon(painter = rememberVectorPainter(...)) appropriately cache VectorPainter instances across recompositions.
• WASM Preview Stubs & Registry: The preview registry additions in SnippetRegistry.kt and WASM stubs (ResStubs.kt, AnnotationStubs.kt, ThemeStubs.kt) correctly delegate multiplatform resource loading without introducing main-thread blocking operations or redundant compositions.

⚡ Jetpack Compose Performance Review

No Jetpack Compose performance issues were found in the changed code.

Summary of Changes Analyzed

An exhaustive scan was performed on all newly introduced and modified Kotlin code (+ lines in .gemini/pr_diff.patch) across the 21 touched files:

• Vector Icon Migration (AppIcons.kt, AppBar.kt, Badges.kt, Chip.kt, Dialog.kt, FloatingActionButton.kt, Menus.kt, Navigation.kt, NavigationDrawer.kt, PullToRefreshBox.kt, Scaffold.kt, SearchBar.kt, SegmentedButton.kt, SwipeToDismissBox.kt, Switch.kt, Tooltips.kt):

  • Replaced external/extended icon dependencies with standalone ImageVector definitions in AppIcons.
  • Icon vectors are instantiated once using Kotlin by lazy singletons on the AppIcons object rather than being allocated inside composable bodies, avoiding composition overhead and GC pressure.
  • Usage of Icon(painter = rememberVectorPainter(AppIcons.<Icon>), ...) correctly caches the VectorPainter in the slot table keyed by the static ImageVector reference.

• Multiplatform WASM Preview Registry & Stubs (SnippetRegistry.kt, ResStubs.kt, AnnotationStubs.kt, ThemeStubs.kt):

  • SnippetRegistry entries provide top-level preview lambdas mapping snippet region tags for WASM rendering and screenshot generation without state observation leaks.
  • Multiplatform resource helpers and theme stubs adhere to Compose idioms without introducing redundant state wrapping, backwards writes, or un-cached computations.

• Visibility & Scoping (SearchBar.kt, SwipeToDismissBox.kt, SnippetsActivity.kt):

  • Minor visibility updates (private fun to fun) and import adjustments maintain the existing composable hierarchy without introducing recomposition regressions.