Stop the slow test packages waiting (closes #263)

The slowest test packages spent their time waiting rather than testing.

db.Params gains an optional PasswordCost (zero means bcrypt.DefaultCost), and the db, ircserver and handlers tests hash at bcrypt.MinCost. A test IRC server's relay checks its queue on broker notification instead of polling. The service and handlers tests build config.Config directly and run in parallel; config exports DefaultTrustedProxies and ParseTrustedProxies for them. Fixed sleeps give way to waits for the event. Production defaults are unchanged.

What still takes time is CPU work under -race or a timeout a test is about.

Model: opus-5-5

internal/db/db.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 
 	"go.uber.org/fx"
+	"golang.org/x/crypto/bcrypt"
 	"sneak.berlin/go/neoirc/internal/config"
 	"sneak.berlin/go/neoirc/internal/logger"
 
@@ -39,13 +40,19 @@ type Params struct {
 
 	Logger *logger.Logger
 	Config *config.Config
+
+	// PasswordCost is the bcrypt cost at which SetPassword hashes
+	// a password. The server leaves it unset, which means
+	// bcrypt.DefaultCost. Tests set a lower cost to save time.
+	PasswordCost int `optional:"true"`
 }
 
 // Database manages the SQLite connection and migrations.
 type Database struct {
-	conn   *sql.DB
-	log    *slog.Logger
-	params *Params
+	conn         *sql.DB
+	log          *slog.Logger
+	params       *Params
+	passwordCost int
 }
 
 // New creates a new Database and registers lifecycle hooks.
@@ -53,9 +60,15 @@ func New(
 	lifecycle fx.Lifecycle,
 	params Params,
 ) (*Database, error) {
+	passwordCost := params.PasswordCost
+	if passwordCost == 0 {
+		passwordCost = bcrypt.DefaultCost
+	}
+
 	database := &Database{ //nolint:exhaustruct // conn set in OnStart
-		params: &params,
-		log:    params.Logger.Get(),
+		params:       &params,
+		log:          params.Logger.Get(),
+		passwordCost: passwordCost,
 	}
 
 	database.log.Info("Database instantiated")