Clean up Graphic Attributes palette

- Revert formatting, import/module reordering and unrelated rewrites
  outside the feature (command.rs, style.rs, paper.rs, view/mod.rs,
  properties.rs, dialog.rs, ValuePromptCommand); the new SVG icons stay.
- Move the palette logic out of dialog.rs into update/graphic_attributes.rs.
- Replace 14 loose app fields and ~50 Message variants by
  GraphicAttributesState (one Menu enum for the open drop-down) and a
  nested GraphicAttributesMsg / GradientMsg, like BlockPaletteMsg.
- Share the selection -> line/fill handles -> unlocked edit path, reuse
  valid_block_name, the ribbon lineweight handler and fill_handles, and
  drop the unused GradientColorToggle, color_open and LineLinetypeScaleInput.
- Linetype scale accepts any positive value (e.g. ISO pen widths 0.13,
  0.18, 0.25, 0.35) instead of rounding to 0.1 with a 0.1 minimum.
- Closing open boundaries and creating the fill is one undo step.
- The close prompt also answers typed Y/N + Enter, a bare Enter (Yes)
  and Escape (cancel), not only the option buttons.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VgkJN8DEojuPTumAXLHotu

src/ui/window/mod.rs

@@ -1,32 +1,32 @@
 pub mod about;
-pub mod alias_editor;
-pub mod annotation_data;
-pub mod attribute_editor;
-pub mod auto_constrain_settings;
 pub mod block_definition;
 pub mod block_palette;
 pub mod browser;
-pub mod drafting_settings;
+pub mod layout_manager;
+pub mod layer_state_manager;
 pub mod drawing_units;
-pub mod find_replace;
 pub mod geometric_tolerance;
 pub mod gradient_editor;
 pub mod graphic_attributes;
-pub mod layer_state_manager;
+pub mod drafting_settings;
+pub mod auto_constrain_settings;
 pub mod layer_translator;
-pub mod layers;
-pub mod layout_manager;
-pub mod missing_fonts;
-pub mod named_parameters;
-pub mod open_progress;
-pub mod options;
 pub mod plot;
-pub mod plugin_manager;
 pub mod print_all;
-pub mod recovery;
+pub mod plugin_manager;
 pub mod shortcuts;
+pub mod layers;
 pub mod update_notice;
-pub mod wblock;
+pub mod open_progress;
+pub mod missing_fonts;
+pub mod recovery;
+pub mod options;
+pub mod attribute_editor;
+pub mod annotation_data;
+pub mod alias_editor;
+pub mod find_replace;
+pub mod named_parameters;
 pub mod xref_attach;
 pub mod xref_help;
 pub mod xref_manager;
+pub mod wblock;