fix: make the reader's typography, width and arrow keys work

Typography was in the stylesheet foliate prepends, which the book overrides;
moved to the appended one. The window keydown handler was never bound.

Also: wider reading area, page on a card, arrows moved onto it, spread gutter,
and the sidebar stays open on chapter clicks.

frontend/src/lib/reader/settings.ts

@@ -12,7 +12,10 @@ export const DEFAULT_READER_SETTINGS: ReaderSettings = {
 	letterSpacing: 0,
 	margin: 48,
 	gap: 6,
-	maxInlineSize: 720,
+	// foliate caps the reading area at this times the column count, so 1000 gives
+	// a 2000px spread — enough to fill a large display rather than leaving the
+	// book as a narrow strip. Its own default of 720 is noticeably tight.
+	maxInlineSize: 1000,
 	maxColumnCount: 2,
 	flow: 'paginated',
 	justify: true,
@@ -30,7 +33,7 @@ export const READER_BOUNDS = {
 	letterSpacing: { min: -0.05, max: 0.2, step: 0.01 },
 	margin: { min: 0, max: 120, step: 4 },
 	gap: { min: 0, max: 15, step: 1 },
-	maxInlineSize: { min: 480, max: 1400, step: 20 }
+	maxInlineSize: { min: 400, max: 2400, step: 20 }
 } as const;
 
 /**