Bundle all the icons together.

src/icons.zig

@@ -0,0 +1,51 @@
+//! The symbolic icons the app names, carried inside the binary.
+//!
+//! Widgets here ask for icons by freedesktop name — `utilities-terminal-
+//! symbolic`, `web-browser-symbolic`, and so on — and by default GTK resolves
+//! those against whatever icon theme the host has installed. Recent
+//! adwaita-icon-theme releases dropped many of these legacy names, so whether
+//! a given machine still shows them is luck. This module removes the luck:
+//! the icons are compiled into the binary as a GResource (see
+//! `assets/icons/icons.gresource.xml` and the glib-compile-resources step in
+//! `build.zig`) and registered with the icon theme at startup.
+//!
+//! Registration is deliberately as a *fallback*: `addResourcePath` folds the
+//! bundle into hicolor, the theme of last resort, so a host theme that does
+//! provide a name keeps winning and the app stays native-looking. The bundle
+//! only answers for names the host can't.
+
+const std = @import("std");
+const gdk = @import("gdk");
+const gio = @import("gio");
+const glib = @import("glib");
+const gtk = @import("gtk");
+
+const data = @embedFile("icons.gresource");
+
+/// Register the bundled icons. Called once at activation, before the first
+/// window is built, so nothing is ever looked up ahead of it.
+///
+/// Failure is logged and swallowed: a missing icon renders as the
+/// broken-image glyph, which is exactly the state this module exists to
+/// avoid, but not a reason to refuse to open a window.
+pub fn init() void {
+    var err: ?*glib.Error = null;
+
+    // newFromData copies if the embedded bytes aren't suitably aligned, so
+    // static is safe here regardless of where @embedFile landed them.
+    const bytes = glib.Bytes.newStatic(data, data.len);
+    defer bytes.unref();
+
+    const resource = gio.Resource.newFromData(bytes, &err) orelse {
+        if (err) |e| {
+            std.log.warn("failed to load bundled icons: {s}", .{e.f_message orelse "unknown"});
+            e.free();
+        }
+        return;
+    };
+    gio.resourcesRegister(resource);
+
+    if (gdk.Display.getDefault()) |display| {
+        gtk.IconTheme.getForDisplay(display).addResourcePath("/dev/greyson/playpen/icons");
+    }
+}

src/main.zig

@@ -12,6 +12,7 @@ const gio = @import("gio");
 const Settings = @import("Settings.zig");
 const Window = @import("Window.zig");
 const appearance = @import("appearance.zig");
+const icons = @import("icons.zig");
 
 /// libghostty-vt logs unimplemented sequences at debug level, which is very
 /// chatty against a real shell. Keep the app's own warnings and errors.
@@ -50,6 +51,10 @@ fn onActivate(app: *adw.Application, _: ?*anyopaque) callconv(.c) void {
     // user chose rather than repainted into it a moment later.
     appearance.init();
 
+    // Same reasoning: the bundled icons are registered before anything asks
+    // for one by name.
+    icons.init();
+
     const window = Window.create(gpa.allocator(), app) catch |err| {
         std.log.err("failed to create window: {s}", .{@errorName(err)});
         return;