Sheet sets: import statuses, view navigation fields, drawing lock files

Import Layouts as Sheets shows the reference's statuses (already part of
a sheet set / may belong to another sheet set / available) and Browse
replaces the list; the Field dialog SheetView tree lists sheet views with
their properties, scale formats and hyperlinks; drawings open in tabs get
.dwl/.dwl2 lock files that other instances read as open; the codec pin
moves to the revision with sheet views and the default output folder.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -4206,7 +4206,7 @@ dependencies = [
 [[package]]
 name = "opencadcodec"
 version = "0.5.5"
-source = "git+https://github.com/ramox81/cadcodec.git?rev=d86f57d#d86f57d5d179bc57fe7826d70454bece40c20320"
+source = "git+https://github.com/ramox81/cadcodec.git?rev=29aff7e#29aff7e8e6f4669cd1f41fc82d39521127c07d03"
 dependencies = [
  "ahash 0.8.12",
  "anyhow",