fix(settings): dupe all strings on first-run to prevent Bus error in deinit

When settings.json does not exist (first run), the FileNotFound branch
returned a Settings struct with comptime string constants from default
(e.g. preferred_mirror = "", proxy = ""). Since deinit() unconditionally
calls allocator.free() on these fields, the GPA attempted to write
@Memset on read-only memory, causing a Bus error at exit.

Dupe all string fields via allocator in the FileNotFound branch so
every string is heap-allocated and safe to free in deinit.

Also show active Zig version after successful upgrade.

Author: lispking

src/settings.zig

@@ -56,9 +56,19 @@ pub const Settings = struct {
     pub fn load(allocator: std.mem.Allocator, io: std.Io, path: []const u8) !Settings {
         const file = std.Io.Dir.cwd().openFile(io, path, .{}) catch |err| switch (err) {
             error.FileNotFound => {
-                // Create new settings file with defaults
-                var settings = default;
-                settings.path = path;
+                // Create new settings file with defaults.
+                // Dupe all string fields so deinit can safely free them all.
+                var settings = Settings{
+                    .version_map_url = try allocator.dupe(u8, default.version_map_url),
+                    .zls_vmu = try allocator.dupe(u8, default.zls_vmu),
+                    .mirror_list_url = try allocator.dupe(u8, default.mirror_list_url),
+                    .use_color = default.use_color,
+                    .always_force_install = default.always_force_install,
+                    .preferred_mirror = try allocator.dupe(u8, default.preferred_mirror),
+                    .mirror_updated_at = default.mirror_updated_at,
+                    .proxy = try allocator.dupe(u8, default.proxy),
+                    .path = path,
+                };
                 try settings.save(allocator, io);
                 return settings;
             },

src/upgrade.zig

@@ -317,6 +317,28 @@ pub fn run(
     try stdout.print("Now running zvm {s}\n", .{latest_version});
     try stdout.flush();
 
+    // Show the active Zig version
+    if (zvm.getActiveVersion(allocator)) |active| {
+        defer allocator.free(active);
+        var ver_buf: [std.fs.max_path_bytes]u8 = undefined;
+        const ver_path = zvm.versionPath(&ver_buf, active);
+        const zig_path = std.fmt.allocPrint(allocator, "{s}/zig", .{ver_path}) catch return;
+        defer allocator.free(zig_path);
+
+        const ver_result = std.process.run(allocator, zvm.io, .{
+            .argv = &.{ zig_path, "version" },
+            .stdout_limit = .limited(1024),
+        }) catch return;
+        defer allocator.free(ver_result.stdout);
+        defer allocator.free(ver_result.stderr);
+
+        if (ver_result.stdout.len > 0) {
+            const ver = std.mem.trim(u8, ver_result.stdout, " \n\r");
+            try stdout.print("Active Zig: {s} ({s})\n", .{ active, ver });
+            try stdout.flush();
+        }
+    }
+
     // Clean up the downloaded archive
     std.Io.Dir.cwd().deleteFile(zvm.io, archive_path) catch {};
 }