Save imgui.ini to %APPDATA%\UsdLayerManager\ instead of CWD

Sets io.IniFilename to %APPDATA%\UsdLayerManager\imgui.ini right after
CreateContext so ImGui never touches the working directory for layout
persistence. The directory is created on first run via create_directories.
m_iniFilePath on ImGuiContext holds the string so the pointer stays valid
for the lifetime of the context.

Also removes imgui.ini from version control and adds it to .gitignore.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -72,3 +72,6 @@ desktop.ini
 # Temporary files
 *.tmp
 *.temp
+
+# ImGui layout (saved to %APPDATA%\UsdLayerManager at runtime)
+imgui.ini

imgui.ini

@@ -1,62 +0,0 @@
-[Window][WindowOverViewport_11111111]
-Pos=0,22
-Size=1920,1093
-Collapsed=0
-
-[Window][Debug##Default]
-Pos=60,60
-Size=400,400
-Collapsed=0
-
-[Window][Scene Hierarchy]
-Pos=0,22
-Size=285,655
-Collapsed=0
-DockId=0x00000001,0
-
-[Window][Layer Panel]
-Pos=60,60
-Size=121,48
-Collapsed=0
-
-[Window][Viewport]
-Pos=287,22
-Size=1286,1003
-Collapsed=0
-DockId=0x00000007,0
-
-[Window][Property Panel]
-Pos=1575,22
-Size=345,1093
-Collapsed=0
-DockId=0x00000006,0
-
-[Window][Stage Info]
-Pos=0,22
-Size=285,655
-Collapsed=0
-DockId=0x00000001,1
-
-[Window][Stage Editor]
-Pos=0,679
-Size=285,436
-Collapsed=0
-DockId=0x00000002,0
-
-[Window][Timeline]
-Pos=287,1027
-Size=1286,88
-Collapsed=0
-DockId=0x00000008,0
-
-[Docking][Data]
-DockSpace       ID=0x08BD597D Window=0x1BBC0F80 Pos=0,22 Size=1920,1093 Split=X
-  DockNode      ID=0x00000005 Parent=0x08BD597D SizeRef=1573,637 Split=X
-    DockNode    ID=0x00000003 Parent=0x00000005 SizeRef=285,637 Split=Y Selected=0xB8729153
-      DockNode  ID=0x00000001 Parent=0x00000003 SizeRef=289,381 Selected=0xB8729153
-      DockNode  ID=0x00000002 Parent=0x00000003 SizeRef=289,254 Selected=0xBE78FE5F
-    DockNode    ID=0x00000004 Parent=0x00000005 SizeRef=1286,637 Split=Y Selected=0xC450F867
-      DockNode  ID=0x00000007 Parent=0x00000004 SizeRef=850,547 CentralNode=1 Selected=0xC450F867
-      DockNode  ID=0x00000008 Parent=0x00000004 SizeRef=850,88 Selected=0x4F89F0DC
-  DockNode      ID=0x00000006 Parent=0x08BD597D SizeRef=345,637 Selected=0xFA2314A6
-

src/ui/ImGuiContext.cpp

@@ -5,6 +5,7 @@
 #include <imgui.h>
 #include <imgui_impl_win32.h>
 #include <imgui_impl_opengl3.h>
+#include <filesystem>
 
 // Forward declare message handler from imgui_impl_win32.cpp
 extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
@@ -94,6 +95,15 @@ bool ImGuiContext::Initialize(const std::string& windowTitle, int width, int hei
     // ImGui window is focused, which would block all viewport hotkeys (F, A, etc.).
     io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
 
+    // Store imgui.ini in %APPDATA%\UsdLayerManager\ so it doesn't litter the CWD.
+    if (const char* appData = getenv("APPDATA")) {
+        std::filesystem::path iniDir =
+            std::filesystem::path(appData) / "UsdLayerManager";
+        std::filesystem::create_directories(iniDir);
+        m_iniFilePath = (iniDir / "imgui.ini").string();
+        io.IniFilename = m_iniFilePath.c_str();
+    }
+
     // Load Inter font.
     // The build directory copies the font as Inter.ttc; the install step renames
     // it to Inter.ttf.  Try .ttf first (install layout), fall back to .ttc (build).

src/ui/ImGuiContext.h

@@ -36,6 +36,7 @@ private:
     bool m_shouldClose;
     int m_width;
     int m_height;
+    std::string m_iniFilePath; // persists for the lifetime of the ImGui context
 };
 
 } // namespace UsdLayerManager