Update Imgui from 1.90.6 to 1.92.5, use Dear Bindings instead of cimgui (#10118)

This updates our Imgui version from 1.90.6 to 1.92.5 which is almost 18
months of changes. In the process, we've also migrated from cimgui to
Dear Bindings, the official way to do C bindings.

This PR doesn't contain any functionality changes, only the dependency
change and API changes necessary to achieve the same behavior.

Author: mitchellh

.gitattributes

@@ -4,7 +4,6 @@ build.zig.zon.json linguist-generated=true
 vendor/** linguist-vendored
 website/** linguist-documentation
 pkg/breakpad/vendor/** linguist-vendored
-pkg/cimgui/vendor/** linguist-vendored
 pkg/glfw/wayland-headers/** linguist-vendored
 pkg/libintl/config.h linguist-generated=true
 pkg/libintl/libintl.h linguist-generated=true

build.zig.zon

@@ -63,7 +63,7 @@
         },
 
         // C libs
-        .cimgui = .{ .path = "./pkg/cimgui", .lazy = true },
+        .dcimgui = .{ .path = "./pkg/dcimgui", .lazy = true },
         .fontconfig = .{ .path = "./pkg/fontconfig", .lazy = true },
         .freetype = .{ .path = "./pkg/freetype", .lazy = true },
         .gtk4_layer_shell = .{ .path = "./pkg/gtk4-layer-shell", .lazy = true },

build.zig.zon.json

@@ -1,4 +1,10 @@
 [
+  {
+    "type": "archive",
+    "url": "https://deps.files.ghostty.org/DearBindings_v0.17_ImGui_v1.92.5-docking.tar.gz",
+    "dest": "vendor/p/N-V-__8AANT61wB--nJ95Gj_ctmzAtcjloZ__hRqNw5lC1Kr",
+    "sha256": "8bfec500e00926f679853ee23d67cc392d3c3181733ca4704738651d3f70baa3"
+  },
   {
     "type": "archive",
     "url": "https://deps.files.ghostty.org/breakpad-b99f444ba5f6b98cac261cbb391d8766b34a5918.tar.gz",
@@ -55,9 +61,9 @@
   },
   {
     "type": "archive",
-    "url": "https://deps.files.ghostty.org/imgui-1220bc6b9daceaf7c8c60f3c3998058045ba0c5c5f48ae255ff97776d9cd8bfc6402.tar.gz",
-    "dest": "vendor/p/N-V-__8AAH0GaQC8a52s6vfIxg88OZgFgEW6DFxfSK4lX_l3",
-    "sha256": "a05fd01e04cf11ab781e28387c621d2e420f1e6044c8e27a25e603ea99ef7860"
+    "url": "https://github.com/ocornut/imgui/archive/refs/tags/v1.92.5-docking.tar.gz",
+    "dest": "vendor/p/N-V-__8AAEbOfQBnvcFcCX2W5z7tDaN8vaNZGamEQtNOe0UI",
+    "sha256": "c816c20e8c75f3e15ae867350e79925502d1a6a85938bb1a73b8927e5f31f9cb"
   },
   {
     "type": "archive",