milestone 32: task-shaped configuration, file mode as a rendering, config status api

src/web/server.zig

@@ -128,6 +128,12 @@ pub const WebState = struct {
     /// loaded the file at T" and nothing more: a file whose mtime is newer has
     /// not been loaded by the running process.
     reconciled_at: ?i64 = null,
+    /// Whether a configuration change this process already committed waits for
+    /// a restart to take effect: the upstream pool and the scalar settings are
+    /// both built at startup. Per-process state, never persisted — nothing
+    /// clears it but process exit, which is exactly what applies the change.
+    /// Only database-mode mutations raise it; file mode never reaches them.
+    restart_pending: std.atomic.Value(bool) = .init(false),
 
     handler: ?*dns_handler.Handler = null,
     pause: ?*pause_mod.Pause = null,