refactor: split every monolithic module into focused submodules

Each source file that had grown beyond a single concern is replaced by an identically-named directory containing focused submodules. `src/event_loop/mod.rs` (878 lines) becomes a directory with clipboard, context_menu, cursor_shape, drag, focus, handlers, invalidation, overlays_reconcile, repeat, run, surface, text_editing, and tooltip. Every widget, input handler, and theme component follows the same split. Public interfaces are unchanged — only the internal file layout moves.
image bumped from 0.25.2 to 0.25.9.

src/input/keyboard/nav.rs

@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: LGPL-2.1-only
+// Copyright (C) 2026 Liberux Labs, S. L. <info@liberux.net>
+
+use crate::app::App;
+use crate::event_loop::{ AppData, SurfaceFocus };
+
+impl<A: App> AppData<A>
+{
+	/// Step the topmost scroll's `hovered_idx` one item up or down with
+	/// the keyboard. Returns `true` when the move was applied (a scroll
+	/// with at least one navigable item was on screen and the new item
+	/// is different from the current hover) so the caller can fall
+	/// through to the application's own `on_key` only on a no-op.
+	///
+	/// The "topmost scroll" is the last entry in `scroll_rects`, which
+	/// matches Stack-overlay layout order: a popup pushed after the
+	/// main content sits above it. Auto-scrolls the new item into view
+	/// by adjusting `scroll_offsets[scroll_idx]`.
+	pub( crate ) fn move_keyboard_hover( &mut self, focus: SurfaceFocus, reverse: bool ) -> bool
+	{
+		// Find the topmost scroll that has a navigable item list.
+		let scroll_meta = {
+			let ss = self.surface( focus );
+			ss.scroll_rects.iter().rev()
+				.find_map( |( rect, idx )|
+				{
+					ss.scroll_navigable_items.get( idx )
+						.filter( |list| !list.is_empty() )
+						.map( |list| ( *rect, *idx, list.clone() ) )
+				} )
+		};
+		let Some( ( scroll_rect, scroll_idx, items ) ) = scroll_meta else { return false; };
+
+		let current  = self.surface( focus ).hovered_idx;
+		let pos      = current.and_then( |h| items.iter().position( |( i, _, _ )| *i == h ) );
+		let next_pos = match ( reverse, pos )
+		{
+			( false, None )      => 0,
+			( false, Some( p ) ) => ( p + 1 ).min( items.len() - 1 ),
+			( true,  None )      => items.len() - 1,
+			( true,  Some( p ) ) => p.saturating_sub( 1 ),
+		};
+		let ( new_idx, content_y, content_h ) = items[ next_pos ];
+
+		// Auto-scroll to bring the new item fully into view. Item Y is
+		// in pre-offset content coordinates, so the offset that places
+		// the item flush with the top of the viewport is `content_y`,
+		// and flush with the bottom is `content_y + content_h - viewport_h`.
+		let viewport_h = scroll_rect.height;
+		let current_offset = self.surface( focus )
+			.scroll_offsets.get( &scroll_idx )
+			.copied().unwrap_or( 0.0 );
+		let new_offset = if content_y < current_offset
+		{
+			content_y
+		}
+		else if content_y + content_h > current_offset + viewport_h
+		{
+			( content_y + content_h - viewport_h ).max( 0.0 )
+		}
+		else
+		{
+			current_offset
+		};
+
+		let ss = self.surface_mut( focus );
+		ss.hovered_idx = Some( new_idx );
+		ss.scroll_offsets.insert( scroll_idx, new_offset );
+		ss.request_redraw();
+		true
+	}
+}