f674224: fix: RSC style tags for extended components have correct href and include base CSS (#5663)

• Fix spaces in <style href> attribute that caused React 19 hydration failures when using styled() inheritance
• Fix missing base component CSS in RSC output when only the extended component renders
• Emit a separate <style> tag per inheritance level with content-aware hrefs, enabling React 19 deduplication of shared base styles
• Preserve correct CSS ordering (base before extended) for proper specificity override behavior

f674224: Reduce standalone/browser bundle size by making IS_RSC a build-time constant, enabling dead code elimination of RSC-specific branches

51ffa9c: Fix createGlobalStyle compatibility with React StrictMode and RSC

This fix addresses issues where global styles would disappear or behave incorrectly in React StrictMode and RSC:

1. Static styles optimization: Static global styles (without props/interpolations) are now only injected once and won't be removed/re-added on every render. This prevents the style flickering that could occur during concurrent rendering.

2. StrictMode-aware cleanup: Style cleanup now uses queueMicrotask to coordinate with React's effect lifecycle. In StrictMode's simulated unmount/remount cycle, styles are preserved. On real unmount, styles are properly removed.

3. RSC compatibility: Move useRef inside RSC guard in createGlobalStyle and unify all useContext calls to use consistent !IS_RSC ? pattern.

4. RSC inline style tag cleanup: Fix bug where server-defined createGlobalStyle rendered in client components would leave behind accumulated SSR-rendered inline <style data-styled-global> tags. The cleanup effect now removes these hoisted style tags when the component unmounts or re-renders with different CSS.

These changes ensure createGlobalStyle works correctly with:

• React StrictMode's double-render behavior
• React 18/19's concurrent rendering features
• React 19's style hoisting with the precedence attribute
• React Server Components (server-defined GlobalStyles in client components)

51ffa9c: Restore styled.br.

1f794b7: Add package.json "exports" field for better native ESM integration.

7ff7002: Fix: Line comments (//) in multiline CSS declarations no longer cause parsing errors (fixes #5613)

JS-style line comments (//) placed after multiline declarations like calc() were not being properly stripped, causing CSS parsing issues. Comments are now correctly removed anywhere in the CSS while preserving valid syntax.

Example that now works:

const Box = styled.div`
  max-height: calc(100px + 200px + 300px); // This comment no longer breaks parsing
  background-color: green;
`;

7ff7002: Fix: Contain invalid CSS syntax to just the affected line

In styled-components v6, invalid CSS syntax (like unbalanced braces) could cause all subsequent styles to be ignored. This fix ensures that malformed CSS only affects the specific declaration, not subsequent valid styles.

Example that now works:

const Circle = styled.div`
  width: 100px;
  line-height: ${() => '14px}'}; // ⛔️ This malformed line is dropped
  background-color: green; // ✅ Now preserved (was ignored in v6)
`;

6e4d1e7: fix: suppress false "created dynamically" warnings in React Server Components

The dynamic creation warning check now properly detects RSC environments and skips validation when IS_RSC is true. This eliminates false warnings for module-level styled components in server components, which were incorrectly flagged due to RSC's different module evaluation context. Module-level styled components in RSC files no longer trigger warnings since they cannot be created inside render functions by definition.

a4b4a6b: fix: include TypeScript declaration files in npm package

Fixed Rollup TypeScript plugin configuration to override tsconfig.json's noEmit setting, ensuring TypeScript declaration files are generated during build.

a4b4a6b: fix: resolve TypeScript error blocking type declaration emission

Fixed TypeScript error in StyledComponent when merging style attributes from attrs. Added explicit type cast to React.CSSProperties to safely merge CSS property objects. This error was preventing TypeScript declaration files from being generated during build.