docs(nix): Update doxygen version

docs/default.nix

@@ -10,7 +10,7 @@
   uv2nix,
   pyproject-build-systems,
   # non-python packages to build docs
-  doxygen,
+  unstable,
   graphviz,
   # ros version to link to with intersphinx - defaults to humble
   rosDistro ? "humble",
@@ -48,7 +48,7 @@ let
     name = "roar-docs-env";
     paths = [
       pyEnv
-      doxygen
+      unstable.doxygen
       graphviz
     ];
   };

docs/nix/overlay.nix

@@ -0,0 +1,20 @@
+final: prev:
+let
+  doxygen = prev.doxygen.overrideAttrs (
+    { ... }:
+    rec {
+      version = "1.12.0";
+      patches = [ ];
+
+      src = prev.fetchFromGitHub {
+        owner = "doxygen";
+        repo = "doxygen";
+        rev = "Release_${prev.lib.replaceStrings [ "." ] [ "_" ] version}";
+        sha256 = "sha256-4zSaM49TjOaZvrUChM4dNJLondCsQPSArOXZnTHS4yI=";
+      };
+    }
+  );
+in
+{
+  inherit doxygen;
+}

docs/nix/shell.nix

@@ -2,7 +2,7 @@
   rosDistro,
   mkShell,
   env,
-  uv,
+  unstable,
   drawio,
 }:
 # provide a dev shell environment for the docs - see pyproject docs:
@@ -16,7 +16,7 @@ let
     ROS_DISTRO = rosDistro;
     buildInputs = [
       env
-      uv # uv added to manage python dependencies
+      unstable.uv # uv added to manage python dependencies - needs to be from unstable due to rapid development
       drawio
     ];
     shellHook = ''

flake.nix

@@ -71,8 +71,7 @@
               ros = final.rosPackages.${rosDistro}.overrideScope (
                 rosFinal: rosPrev: { manualDomainId = toString productionDomainId; }
               );
-              # override select packages with latest
-              inherit (pkgs-unstable) uv;
+              unstable = pkgs-unstable;
             })
           ];
           # Gazebo makes use of Freeimage.
@@ -83,6 +82,9 @@
         # we don't need to apply overlays here since pkgs-unstable is only for pure python stuff
         pkgs-unstable = import nixpkgs-unstable {
           inherit system;
+          overlays = [
+            (import ./docs/nix/overlay.nix)
+          ];
           config.allowUnfree = true; # needed for draw.io for the docs
         };
 
@@ -153,7 +155,6 @@
         };
 
         # --- PYTHON (UV) WORKSPACES ---
-        # note: called with pkgs-unstable since we need the uv tool to be up-to-date due to rapid development
         # note: called with rosDistro to link correct intersphinx inventory
         docs = pkgs.callPackage (import ./docs) {
           inherit