feat: add SQLite support, setup wizard enhancements, and live dashboard

Add zero-dependency SQLite mode so users can run Erupe without
PostgreSQL. A transparent db.DB wrapper auto-translates PostgreSQL
SQL ($N placeholders, now(), ::casts, ILIKE, public. prefix,
TRUNCATE) for SQLite at runtime — all 28 repo files use the wrapper
with no per-query changes needed.

Setup wizard gains two new steps: quest file detection with download
link, and gameplay presets (solo/small/community/rebalanced). The API
server gets a /dashboard endpoint with auto-refreshing stats.

CI release workflow now builds and pushes Docker images to GHCR
alongside binary artifacts on tag push.

Key changes:
- common/db: DB/Tx wrapper with 6 SQL translation rules
- server/migrations/sqlite: full SQLite schema (0001-0005)
- config: Database.Driver field ("postgres" or "sqlite")
- main.go: SQLite connection with WAL mode, single writer
- server/setup: quest check + preset selection steps
- server/api: /dashboard with live stats
- .github/workflows: Docker in release, deduplicate docker.yml

server/signserver/sign_server.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"sync"
 
+	dbutil "erupe-ce/common/db"
 	cfg "erupe-ce/config"
 	"erupe-ce/network"
 	"github.com/jmoiron/sqlx"
@@ -38,9 +39,10 @@ func NewServer(config *Config) *Server {
 		erupeConfig: config.ErupeConfig,
 	}
 	if config.DB != nil {
-		s.userRepo = NewSignUserRepository(config.DB)
-		s.charRepo = NewSignCharacterRepository(config.DB)
-		s.sessionRepo = NewSignSessionRepository(config.DB)
+		wdb := dbutil.Wrap(config.DB)
+		s.userRepo = NewSignUserRepository(wdb)
+		s.charRepo = NewSignCharacterRepository(wdb)
+		s.sessionRepo = NewSignSessionRepository(wdb)
 	}
 	return s
 }