Remove deprecated JSON encoder/decoder and update dependencies

- Deleted the custom JSON encoder/decoder implementation in favor of the standard library's `encoding/json` package.
- Removed the `next.orly.dev/pkg/encoders/json` package and its associated files.
- Updated `go.mod` to remove the `github.com/nostr-dev-kit/ndk` dependency and bump the version of `lol.mleku.dev` from v1.0.3 to v1.0.4.
- Cleaned up import statements across various files to reflect the removal of the custom JSON package.
- Ensured that all references to the old JSON encoding/decoding methods are replaced with the standard library equivalents.

pkg/database/subscriptions.go

@@ -7,8 +7,9 @@ import (
 	"strings"
 	"time"
 
+	"encoding/json"
+
 	"github.com/dgraph-io/badger/v4"
-	"next.orly.dev/pkg/encoders/json"
 )
 
 type Subscription struct {
@@ -192,7 +193,7 @@ func (d *D) GetPaymentHistory(pubkey []byte) ([]Payment, error) {
 // IsFirstTimeUser checks if a user is logging in for the first time and marks them as seen
 func (d *D) IsFirstTimeUser(pubkey []byte) (bool, error) {
 	key := fmt.Sprintf("firstlogin:%s", hex.EncodeToString(pubkey))
-	
+
 	isFirstTime := false
 	err := d.DB.Update(
 		func(txn *badger.Txn) error {
@@ -212,6 +213,6 @@ func (d *D) IsFirstTimeUser(pubkey []byte) (bool, error) {
 			return err // Return any other error as-is
 		},
 	)
-	
+
 	return isFirstTime, err
 }