Implement geo backend, TS client, frontend, and CI tests.

Add a Go HTTP API with Ed25519 auth and invitation onboarding, user-scoped GeoJSON Point management, a Bun-tested @noble/ed25519 TypeScript client, static Vue/Vuetify frontend integration, and a Gitea CI workflow running both Go and Bun test suites.

Made-with: Cursor

internal/auth/crypto.go

@@ -0,0 +1,44 @@
+package auth
+
+import (
+	"crypto/ed25519"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+)
+
+func NewRandomToken(byteLen int) (string, error) {
+	if byteLen <= 0 {
+		return "", errors.New("byteLen must be greater than zero")
+	}
+
+	b := make([]byte, byteLen)
+	if _, err := rand.Read(b); err != nil {
+		return "", fmt.Errorf("read random bytes: %w", err)
+	}
+	return base64.RawURLEncoding.EncodeToString(b), nil
+}
+
+func VerifySignature(publicKeyBase64, message, signatureBase64 string) error {
+	pubBytes, err := base64.RawURLEncoding.DecodeString(publicKeyBase64)
+	if err != nil {
+		return fmt.Errorf("decode public key: %w", err)
+	}
+	if len(pubBytes) != ed25519.PublicKeySize {
+		return errors.New("invalid public key length")
+	}
+
+	sigBytes, err := base64.RawURLEncoding.DecodeString(signatureBase64)
+	if err != nil {
+		return fmt.Errorf("decode signature: %w", err)
+	}
+	if len(sigBytes) != ed25519.SignatureSize {
+		return errors.New("invalid signature length")
+	}
+
+	if !ed25519.Verify(ed25519.PublicKey(pubBytes), []byte(message), sigBytes) {
+		return errors.New("signature verification failed")
+	}
+	return nil
+}