fix(pdf): follow-ups to the PDF underlay merge

- Pin cadcodec upstream at d290dbe (the merged underlay change) and
  cadkernel at 4134ae3, which follows it; drop the fork patch, move the
  plugin-API and web-worker crates and the Python plugin lock to the same
  codec so one copy is built.
- "Import as block" with raster images left IMAGE entities without an
  image definition: block definition now creates it like add_entity does,
  through one shared helper.
- The three preview outlines (attach frame, clip boundary, import area)
  stay f64 instead of casting world points to f32.
- Page size / total / PDF scale entries use the catalog's positional
  placeholder; the bare {name} form failed to format in 20 locales.
- The Underlay Layers bulb is the SVG layer icon, not a text glyph.
- PDF dialogs use the shared dialog buttons and radios.
- Options opened from a PDF dialog clears its saved state on return.
- Paper-space underlay background reuses the model block handle already
  resolved; dead `let _ = i` lines and a misplaced doc comment removed.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Cargo.toml

@@ -33,9 +33,9 @@ rfd = "0.17"
 clap = { version = "4", features = ["derive", "string"] }
 env_logger = "0.11"
 log = "0.4"
-acadrust = { git = "https://github.com/ramox81/cadcodec.git", rev = "d290dbe", features = ["serde"] }
-cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "6eae7c9", features = ["acis", "offset"] }
-cadkernel-constraints = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "6eae7c9" }
+acadrust = { git = "https://github.com/HakanSeven12/cadcodec.git", rev = "d290dbe", features = ["serde"] }
+cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "4134ae3", features = ["acis", "offset"] }
+cadkernel-constraints = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "4134ae3" }
 dwg-thumbnailer = { path = "crates/dwg-thumbnailer" }
 flate2 = "1"
 image = { version = "0.25", default-features = false, features = ["png", "jpeg", "bmp", "tiff"] }
@@ -81,9 +81,6 @@ objc2-app-kit = { version = "0.2", features = ["NSApplication", "NSResponder", "
 block2 = "0.5"
 objc2-foundation = { version = "0.2", features = ["NSArray", "NSURL", "NSString", "NSObject", "NSNotification", "NSThread", "NSEnumerator"] }
 
-[patch."https://github.com/HakanSeven12/cadcodec.git"]
-acadrust = { git = "https://github.com/ramox81/cadcodec.git", rev = "d290dbe" }
-
 [patch.crates-io]
 iced_core = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0aad9e00b9327cb7b8546ed84db39" }
 iced_widget = { git = "https://github.com/iced-rs/iced.git", rev = "23604ff22ab0aad9e00b9327cb7b8546ed84db39" }