docs(db-mysql): fix fictional launcher.Register/health.Register in doc examples

The package-doc examples showed a fictional launcher.Register / health.Register
API (and launcher.Append as a package func). Corrected to the real wiring:
lc.Append + web/health.NewHandler(...).ServeHTTP.

Documentation-only. No code, API, or dependency changes; version stays v1.1.0
(the v1.1.0 tag is moved to include this fix). Verified by compiling the
corrected pattern against the real API.

README.md

@@ -19,8 +19,9 @@
 import dbmysql "code.nochebuena.dev/einherjar/db-mysql"
 
 db := dbmysql.New(logger, dbmysql.DefaultConfig())
-launcher.Append(db)   // OnInit opens pool; OnStop closes it
-health.Register(db)   // PING health check; LevelCritical
+lc.Append(db)   // OnInit opens pool; OnStop closes it
+// db is observability.Checkable (PING health check, LevelCritical):
+srv.Get("/health", health.NewHandler(logger, db).ServeHTTP)
 ```
 
 ### Querying

doc.go

@@ -14,8 +14,12 @@
 // # Lifecycle Registration
 //
 //	db := mysql.New(logger, cfg)
-//	launcher.Register(db)
-//	health.Register(db)
+//	lc.Append(db) // lifecycle: OnInit → OnStart → OnStop
+//
+// db satisfies [observability.Checkable], so it can back a health endpoint via
+// web/health.NewHandler:
+//
+//	srv.Get("/health", health.NewHandler(logger, db).ServeHTTP)
 //
 // # Querying
 //