Add user authentication and game persistence with SQLite

- User registration/login with bcrypt password hashing
- SQLite database with goose migrations and sqlc-generated queries
- Games and players persisted to database, resumable after restart
- Guest play still supported alongside authenticated users
- Auth UI components (login/register forms, auth header, guest banner)

go.mod

@@ -8,8 +8,25 @@ require (
 	github.com/CAFxX/httpcompression v0.0.9 // indirect
 	github.com/alexedwards/scs/v2 v2.9.0 // indirect
 	github.com/andybalholm/brotli v1.2.0 // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/klauspost/compress v1.18.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mfridman/interpolate v0.0.2 // indirect
+	github.com/ncruces/go-strftime v1.0.0 // indirect
+	github.com/pressly/goose/v3 v3.26.0 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	github.com/sethvargo/go-retry v0.3.0 // indirect
 	github.com/starfederation/datastar-go v1.0.3 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
+	golang.org/x/sync v0.17.0 // indirect
+	golang.org/x/sys v0.40.0 // indirect
 	maragu.dev/gomponents v1.2.0 // indirect
+	modernc.org/libc v1.67.4 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
+	modernc.org/sqlite v1.44.0 // indirect
 )