Send fx's own events through the service's logger (closes #183)

fx printed its dependency graph and lifecycle hooks through its own console logger on standard error, so an operator shipping the JSON log to a collector got a second shape on a second stream for every start. The production app now passes fx.WithLogger with a small FxLogger in internal/logger that writes fx's events through the service's logger: graph events at debug, lifecycle at info, failures at error. Its constructor takes the configuration, so DEBUG=true applies before fx replays the events it held back. go.uber.org/fx moves from v1.20.1 to v1.24.0. Tests keep fx.NopLogger. The README says a failure before the logger exists, and the Go runtime's own output, still go to standard error as plain text.

Model: opus-5-5

cmd/webhooker/main.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"go.uber.org/fx"
+	"go.uber.org/fx/fxevent"
 	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/database"
 	"sneak.berlin/go/webhooker/internal/datadir"
@@ -168,6 +169,19 @@ func run(stderr io.Writer) int {
 func newApp() *fx.App {
 	return fx.New(
 		fx.StopTimeout(stopTimeout),
+		// fx's own events go through the service's logger, not fx's
+		// console logger on standard error. The exception is a failure
+		// before this logger is built, such as an invalid configuration
+		// value, which fx's console logger still prints there. fx holds
+		// its events back until this logger is built and then replays
+		// them, so it takes the configuration, which sets the level
+		// DEBUG=true asks for: without it the replay would run at INFO
+		// and drop every record of how the graph was built.
+		fx.WithLogger(
+			func(l *logger.Logger, _ *config.Config) fxevent.Logger {
+				return logger.NewFxLogger(l.Get())
+			},
+		),
 		fx.Provide(
 			globals.New,
 			logger.New,