Style deduplication consistency across ThemeProvider v4-to-v5 transition

The global CSS registry in styled-components guarantees that identical style definitions share a single <style> tag, preventing duplication even when components render multiple times. This behavior is central to both the ThemeProvider inject and the withTheme higher‑order component, and it is further refined by the useTheme hook introduced in v5. A precise design question emerges when a theme change triggers a component retry or re‑mount: does the registry retain its prior style‑key mapping, or does a new theme injection risk inserting an additional <style> tag? Version migration from v4, where theming relied solely on the withTheme HOC, to v5, which adds the useTheme hook and a revised style‑generation pipeline, adds a compatibility boundary that may affect how deduplication keys are generated and persisted across unmount‑mount cycles. Server‑side rendering with a StyleManager adds another layer, as hydration mismatches can occur if the registry state is not synchronized between initial render and client takeover.

• Does the StyleManager re‑register style rules when ThemeProvider re‑injects a theme during an async retry?
• How does the v4-to-v5 transition shift the deduplication key schema during dynamic theming retries?
• Is there a documented reconciliation path for style‑tag persistence when component identity changes alongside theme propagation?