fix(connection): Happ TV connect renders through the active block style (all 4)

The TV quick-connect was rendered as standalone cards inserted between two
sliced block lists, which broke the panel's chosen style (e.g. split the
timeline rail) and dropped a step. Now it renders THROUGH the active renderer:

- Blocks gain an optional customNode; every renderer (cards/timeline/accordion/
  minimal) drops it into the block body, so it inherits that exact style.
- InstallationGuide renders the FULL block list in the active style and injects
  the TV connect widget as customNode on the "add subscription" step (no more
  slicing / dropped steps) — only for the Happ Android TV app.
- TvQuickConnect is now content-only (no one-off cards/titles); the block step is
  the wrapper. Buttons already use the shared blockButtonClass.

src/components/connection/blocks/index.ts

@@ -3,4 +3,4 @@ export { TimelineBlock } from './TimelineBlock';
 export { AccordionBlock } from './AccordionBlock';
 export { MinimalBlock } from './MinimalBlock';
 export { BlockButtons } from './BlockButtons';
-export type { BlockRendererProps } from './types';
+export type { BlockRendererProps, RenderBlock } from './types';