Fix fullscreen exit header state

- Clear fullscreen shell state when exiting fullscreen
- Collapse/hide header details after fullscreen exit
- Sync fullscreenchange, toggle label, and details state
- Preserve tool-specific header wording

Author: DavidQ

docs/dev/commit_comment.txt

@@ -1,6 +1 @@
-Fix Parallax Scene Studio header metadata and toggle labels
-
-- Add required Parallax Scene Studio header/intro metadata
-- Remove configuration error for complete tool metadata
-- Replace generic header/details toggle labels with tool-specific text
-- Preserve actionable errors for genuinely missing metadata
+Fix fullscreen header summary state text and single-line collapsed layout - PR 10.15