Redesign Select Color panel: index and true color tabs

Replace the old index page and the iced_aw ColorPicker popup with one
Select Color panel:

- Index Color tab: standard colors, ACI 10-249 grid, grays; arrow keys
  move through the palette.
- True Color tab: HSB, RGB and gradient-field modes built on two new
  widgets (GradientSlider, ColorArea) and iced_aw NumberInput boxes,
  an editable hex field and a nearest/exact index color button.
- Current/New swatch: clicking Current reverts. A mixed selection opens
  on the color of the most recently drawn object with *VARIES* on top.
- Color field accepts an index, a color name, r,g,b or hex.
- Enter confirms, Esc cancels, other keys stay in the panel.
- New labels translated in all 22 locales.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013rGmDUNr1hUf4zo1X3dak8

Cargo.toml

@@ -27,7 +27,7 @@ url = "2"
 iced = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0aad9e00b9327cb7b8546ed84db39", features = ["image", "svg", "advanced", "canvas", "smol", "markdown"] }
 iced_runtime = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0aad9e00b9327cb7b8546ed84db39" }
 iced_core = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0aad9e00b9327cb7b8546ed84db39" }
-iced_aw = { git = "https://github.com/HakanSeven12/iced_aw.git", branch = "agent/fix-iced-fonts", features = ["menu", "context_menu", "color_picker", "drop_down"] }
+iced_aw = { git = "https://github.com/HakanSeven12/iced_aw.git", branch = "agent/fix-iced-fonts", features = ["menu", "context_menu", "color_picker", "drop_down", "number_input"] }
 bytemuck = { version = "1.25", features = ["derive"] }
 glam = { version = "0.33", features = ["bytemuck"] }
 rfd = "0.17"