feat: centralize Barkfile schema

schema.go

@@ -0,0 +1,38 @@
+// Package barkfile parses, validates, and watches Barkfile configuration.
+package barkfile
+
+import "time"
+
+// Config is the typed representation of a Barkfile.
+type Config struct {
+	Listen    string
+	TLS       TLSConfig
+	Databases []DatabaseConfig
+}
+
+// TLSConfig identifies the certificate material used to terminate client TLS.
+type TLSConfig struct {
+	CertFile string
+	KeyFile  string
+}
+
+// DatabaseConfig describes one PostgreSQL database. Hostname is optional:
+// clients without TLS SNI route by the database's configured Name. Exactly one
+// of Upstream and Postgres must be configured.
+type DatabaseConfig struct {
+	Name     string
+	Hostname string
+	Upstream string
+	Postgres *PostgresConfig
+}
+
+// PostgresConfig declares a PawSQL-managed PostgreSQL container. IdleTimeout
+// starts after the last proxied client session closes. TrafficIdleTimeout
+// applies to open sessions with no proxied bytes. Zero disables either timeout.
+type PostgresConfig struct {
+	Image              string
+	Volume             string
+	PasswordEnv        string
+	IdleTimeout        time.Duration
+	TrafficIdleTimeout time.Duration
+}