feat(03-01): add shared postgres pool and plugin migrations

Open one pgx stdlib *sql.DB, hand it to GORM, and run per-plugin
gormigrate sets with isolated history tables after an ICU pl-PL check.

Co-authored-by: Cursor <cursoragent@cursor.com>

go.mod

@@ -6,7 +6,9 @@ toolchain go1.27.0
 
 require (
 	github.com/fsnotify/fsnotify v1.10.1
+	github.com/go-gormigrate/gormigrate/v2 v2.1.7
 	github.com/goccy/go-yaml v1.19.2
+	github.com/jackc/pgx/v5 v5.10.0
 	github.com/knadh/koanf/parsers/yaml v1.1.1
 	github.com/knadh/koanf/providers/confmap v1.0.1
 	github.com/knadh/koanf/providers/env/v2 v2.0.1
@@ -14,15 +16,25 @@ require (
 	github.com/knadh/koanf/v2 v2.3.6
 	github.com/spf13/cobra v1.10.2
 	golang.org/x/term v0.46.0
+	gorm.io/driver/postgres v1.6.3
+	gorm.io/gorm v1.31.2
 )
 
 require (
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
+	github.com/jackc/puddle/v2 v2.2.2 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/knadh/koanf/maps v0.1.2 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/rogpeppe/go-internal v1.16.0 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.48.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
 )