all: remove koka code, move go to repo root

race.go

@@ -0,0 +1,46 @@
+package horse
+
+type RaceID int32
+
+// Race is the internal data about a race.
+type Race struct {
+	ID        RaceID `json:"race_id"`
+	Name      string `json:"name"`
+	Thumbnail int    `json:"thumbnail"`
+	// Some careers contain unusual versions of races, e.g. Tenno Sho (Spring)
+	// in Hanshin instead of Kyoto for Narita Taishin and Biwa Hayahide.
+	// For such races, this field holds the normal race ID.
+	Primary RaceID `json:"primary"`
+}
+
+type SaddleID int32
+
+// Saddle is the internal data about a race win saddle.
+type Saddle struct {
+	ID    SaddleID   `json:"saddle_id"`
+	Name  string     `json:"name"`
+	Races []RaceID   `json:"races"`
+	Type  SaddleType `json:"type"`
+	// Saddles that involve alternate races are themselves alternate.
+	// For such saddles, this field holds the normal saddle ID.
+	Primary SaddleID `json:"primary"`
+}
+
+type SaddleType int8
+
+const (
+	// Saddle for multiple race wins, e.g. Classic Triple Crown, Dual Grand Prix, &c.
+	SaddleTypeHonor SaddleType = iota
+	SaddleTypeG3
+	SaddleTypeG2
+	SaddleTypeG1
+)
+
+type ScenarioID int8
+
+// Scenario is metadata about a career scenario.
+type Scenario struct {
+	ID    ScenarioID `json:"scenario_id"`
+	Name  string     `json:"name"`
+	Title string     `json:"title"`
+}