Select Color: Document and Color books tabs

Document tab: every concrete colour the drawing uses (objects, block
definitions and layers), found in one pass when the panel opens, as a
grid of swatches sortable by recently used, most used, colour and colour
number. The recently-used list is now kept per drawing, so the ribbon's
Recent row shows this drawing's colours.

Color books tab: load AutoCAD .acb colour books (remembered in the
settings on desktop), browse them page by page with the page strip,
search by name and see the RGB equivalent. A book colour is applied as
RGB plus its BOOK$NAME identity on objects and layers instead of
dropping the name.

Strings translated into all 22 locales.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_013rGmDUNr1hUf4zo1X3dak8

src/app/document.rs

@@ -277,6 +277,8 @@ pub(super) struct DocumentTab {
     /// Model-space corners of the last crossing window drawn with no command
     /// running: STRETCH on that selection stretches through it (#1068).
     pub(super) last_crossing_window: Option<([f64; 2], [f64; 2])>,
+    /// Colours picked in this drawing this session, newest first. Not saved.
+    pub(super) recent_colors: Vec<codec::types::Color>,
 }
 
 impl DocumentTab {
@@ -679,6 +681,7 @@ impl DocumentTab {
             suspended_cmd: None,
             transparent_resume: false,
             last_crossing_window: None,
+            recent_colors: Vec::new(),
         }
     }