Remove zig build check step and fix stale references

The check step was a compile-only shortcut that avoided linking when
the pre-built .a files from build.sh were not yet available.  Now that
zig build fetches and builds ghostty as a dependency, the check step
triggers the same full ghostty build — it is no longer faster than a
regular zig build.

Also update stale references: ghostel.el header and README now say
Zig 0.15.2+ with no submodule mention, and the local ghostty override
uses zig fetch --save (--override-dep does not exist in Zig 0.15).

Author: dakra

build.zig

@@ -8,11 +8,11 @@ pub fn build(b: *std.Build) void {
     const is_release = optimize != .Debug;
     const target_os = target.result.os.tag;
     const emacs_module_dir = resolveEmacsModuleDir(b);
-    const ghostty_dep = b.lazyDependency("ghostty", .{
+    const ghostty_dep = b.dependency("ghostty", .{
         .target = target,
         .optimize = optimize,
         .@"emit-lib-vt" = true,
-    }) orelse @panic("ghostty dependency unavailable; run: zig build --fetch");
+    });
 
     const ghostty_lib = ghostty_dep.artifact("ghostty-vt-static");
 

build.zig.zon

@@ -7,7 +7,6 @@
         .ghostty = .{
             .url = "https://github.com/ghostty-org/ghostty/archive/01825411ab2720e47e6902e9464e805bc6a062a1.tar.gz",
             .hash = "ghostty-1.3.2-dev-5UdBCzaaBwVjJOr-ltYINjybeEOAmLAauH5oq8-cdNGN",
-            .lazy = true,
         },
     },
 }