switched to fully self contained docker

internal/app/server.go

@@ -17,7 +17,7 @@ import (
 	"strings"
 	"time"
 
-	_ "github.com/go-sql-driver/mysql"
+	_ "modernc.org/sqlite"
 )
 
 //go:embed templates/*.html static/*
@@ -110,13 +110,15 @@ type pageData struct {
 }
 
 func New(cfg Config) (*Server, error) {
-	db, err := sql.Open("mysql", cfg.DatabaseDSN)
+	db, err := sql.Open("sqlite", cfg.DatabaseDSN)
 	if err != nil {
 		return nil, err
 	}
 	db.SetConnMaxLifetime(5 * time.Minute)
-	db.SetMaxOpenConns(20)
-	db.SetMaxIdleConns(10)
+	// A single writer connection avoids SQLITE_BUSY errors while WAL mode still
+	// permits concurrent readers. This service is intentionally single-node.
+	db.SetMaxOpenConns(1)
+	db.SetMaxIdleConns(1)
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()