Add initial backend

backend/go.mod

@@ -0,0 +1,3 @@
+module git.chandlerswift.com/chandlerswift/fishfryfinder
+
+go 1.23.0

backend/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"embed"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/fs"
+	"net/http"
+	"runtime/debug"
+)
+
+//go:embed dist/*
+var embeddedFiles embed.FS
+
+var buildInfoJSON []byte
+
+func main() {
+	port := flag.Int("port", 8000, "Port to listen on")
+	flag.Parse()
+
+	frontend, err := fs.Sub(embeddedFiles, "dist")
+	if err != nil {
+		panic(err)
+	}
+	http.Handle("GET /", http.FileServer(http.FS(frontend)))
+
+	initializeBuildInfoJSON()
+	http.HandleFunc("GET /api/v1/version", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write(buildInfoJSON)
+	})
+
+	fmt.Printf("Serving on :%v\n", *port)
+	panic(http.ListenAndServe(fmt.Sprintf(":%v", *port), nil))
+}
+
+func initializeBuildInfoJSON() {
+	rawBuildInfo, _ := debug.ReadBuildInfo()
+	var revision, time string
+	var dirty bool
+	for _, buildSetting := range rawBuildInfo.Settings {
+		if buildSetting.Key == "vcs.revision" {
+			revision = buildSetting.Value
+		} else if buildSetting.Key == "vcs.time" {
+			time = buildSetting.Value
+		} else if buildSetting.Key == "vcs.modified" {
+			dirty = buildSetting.Value == "true"
+		}
+	}
+	buildInfo := map[string]interface{}{
+		"GitRev":       revision,
+		"GitDirty":     dirty,
+		"GitTime":      time,
+		"GoVersion":    rawBuildInfo.GoVersion,
+		"AllBuildInfo": rawBuildInfo.String(),
+	}
+
+	var err error
+	buildInfoJSON, err = json.Marshal(buildInfo)
+	if err != nil {
+		panic(err)
+	}
+}