refactor: framework modules log through diary components

- Each module logs through diary.For(<package>): cabana, lagoon, attach, cooler, postcard, beachcomber, lighthouse, centrifugo, flare, phrasebook, wristband, bouncer
- App-published *slog.Logger overrides stay first; messages and attributes unchanged
- sunscreen: InstallDefault documented as the compatibility entry point; diary wraps every channel
- READMEs list diary as a dependency; logging docs: plugins use diary.For

modules/postcard/README.md

@@ -114,7 +114,7 @@ func TestWelcomeMail(t *testing.T) {
 | `postcard.Driver` | Delivers a `postcard.RenderedMessage`. |
 | `postcard.RenderedMessage` | The validated payload a driver transmits: headers, HTML part and text part. |
 | `postcard.NewMemoryDriver` | In-memory driver; `postcard.MemoryDriver.Messages` returns what was sent. |
-| `postcard.NewLogDriver` | Driver that logs through a `*slog.Logger` (the default logger when nil). |
+| `postcard.NewLogDriver` | Driver that logs through a `*slog.Logger` (the postcard component logger when nil). |
 | `postcard.NewSMTPDriver` | SMTP driver built from a `postcard.SMTPConfig`. |
 | `postcard.SMTPConfig` | Host, port, credentials, TLS policy and timeout for the SMTP driver. |
 | `postcard.FailDriver` | Driver whose `postcard.FailDriver.Send` always returns `postcard.FailDriver.Err`. |
@@ -150,7 +150,7 @@ mail:
 
 ## Dependencies
 
-- SummerCMS modules: [backpack](../backpack/README.md), [compass](../compass/README.md), [pact](../pact/README.md).
+- SummerCMS modules: [backpack](../backpack/README.md), [compass](../compass/README.md), [diary](../diary/README.md) (component logger `postcard` when the app publishes no logger), [pact](../pact/README.md).
 - Third-party: `github.com/wneessen/go-mail` (SMTP), `github.com/yuin/goldmark` (Markdown).
 - Standard library: `bytes`, `context`, `embed`, `fmt`, `html/template`, `io/fs`, `log/slog`, `net/mail`, `regexp`, `strings`, `sync`, `text/template`, `time`.
 - Tests additionally use `github.com/testcontainers/testcontainers-go` (Mailpit container).

modules/postcard/drivers.go

@@ -80,10 +80,11 @@ type LogDriver struct {
 	log *slog.Logger
 }
 
-// NewLogDriver logs through log. slog.Default is used when log is nil.
+// NewLogDriver logs through log. The postcard component logger (diary) is
+// used when log is nil.
 func NewLogDriver(log *slog.Logger) *LogDriver {
 	if log == nil {
-		log = slog.Default()
+		log = moduleLog
 	}
 	return &LogDriver{log: log}
 }

modules/postcard/mailer.go

@@ -9,9 +9,14 @@ import (
 
 	"git.golem15.com/golem15/summercms/modules/backpack"
 	"git.golem15.com/golem15/summercms/modules/compass"
+	"git.golem15.com/golem15/summercms/modules/diary"
 	"git.golem15.com/golem15/summercms/modules/pact"
 )
 
+// moduleLog is postcard's logger: records carry component=postcard and follow
+// log.components.postcard (diary).
+var moduleLog = diary.For("postcard")
+
 // Message is the Send contract for plugin callers.
 type Message struct {
 	Template string
@@ -158,7 +163,7 @@ func loggerFromApp(app *backpack.App) *slog.Logger {
 			return log
 		}
 	}
-	return slog.Default()
+	return moduleLog
 }
 
 // BootPlugin registers a plugin's declared mail templates and layouts.