plan/11: Add GET /api/version endpoint

Adds handlers/version.go returning hardcoded {"version":"0.1.0","name":"director","commit":"unknown"},
wires GET /api/version into main.go next to /api/health, and adds
handlers/version_test.go using httptest (no DB dependency).

Co-Authored-By: director-agent <director-agent@dragonchain.com>

api/handlers/version.go

@@ -0,0 +1,17 @@
+package handlers
+
+import "github.com/gin-gonic/gin"
+
+type VersionResponse struct {
+	Version string `json:"version"`
+	Name    string `json:"name"`
+	Commit  string `json:"commit"`
+}
+
+func (h *Handler) GetVersion(c *gin.Context) {
+	c.JSON(200, VersionResponse{
+		Version: "0.1.0",
+		Name:    "director",
+		Commit:  "unknown",
+	})
+}