web: fix compile errors and critical runtime errors

packages/web/build.zig

@@ -14,6 +14,22 @@ pub fn build(b: *std.Build) void {
         .root_module = module,
     });
 
+    const exe_module = b.createModule(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = target,
+        .optimize = optimize,
+        .imports = &.{
+            .{ .name = "web", .module = module },
+        },
+    });
+
+    const exe = b.addExecutable(.{
+        .name = "web",
+        .root_module = exe_module,
+    });
+
+    b.installArtifact(exe);
+
     const run_tests = b.addRunArtifact(tests);
 
     const test_step = b.step("test", "Run tests");