Add initial RBS support with Steep and TypeProf

sig/nostr/filter.rbs

@@ -0,0 +1,25 @@
+module Nostr
+  class Filter
+    attr_reader ids: Array[String]
+    attr_reader authors: Array[String]
+    attr_reader kinds: Array[Integer]
+    attr_reader e: String
+    attr_reader p: String
+    attr_reader since: Integer
+    attr_reader until: Integer
+    attr_reader limit: Integer
+
+    def initialize: (**untyped) -> void
+    def to_h: -> {
+      ids: Array[String],
+      authors: Array[String],
+      kinds: Array[Integer],
+      e: String,
+      p: String,
+      since: Integer,
+      until: Integer,
+      limit: Integer
+    }
+    def ==: (Filter other) -> bool
+  end
+end