feat(14.3-01): give summer new apps a key, compose, agent notes and a first commit

- .env (0600) with a fresh lagoon.GenerateAppKey key and the compose DSN;
  .env.example without a key
- compose.yaml runs postgres:16 on 127.0.0.1:54320 with a healthcheck
- .gitignore, CLAUDE.md with AGENTS.md as a relative symlink
- git init on main and one commit, with a fallback identity only when git
  has none; git failures are warnings; --no-git skips it
- print the next steps after creating the app

Claude-Session: https://claude.ai/code/session_01M8Qu9LgCKYy7iYEho52tW8

cmd/summer/main.go

@@ -9,6 +9,7 @@ import (
 	"git.golem15.com/golem15/summercms/internal/build"
 	"git.golem15.com/golem15/summercms/internal/dev"
 	"git.golem15.com/golem15/summercms/modules/bonfire"
+	"git.golem15.com/golem15/summercms/modules/lagoon"
 )
 
 func main() {
@@ -311,6 +312,7 @@ func newCommand() bonfire.Command {
 		Flags: []bonfire.Flag{
 			{Name: "framework", Description: "Path to the framework checkout (default: a sibling summercms or summercms.go checkout)"},
 			{Name: "no-plugin", Description: "Do not create the starter plugin", Bare: true},
+			{Name: "no-git", Description: "Do not initialise a git repository", Bare: true},
 		},
 		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
 			name, ok := in.Argument("name")
@@ -322,11 +324,17 @@ func newCommand() bonfire.Command {
 				return err
 			}
 			framework, _ := in.Flag("framework")
+			key, err := lagoon.GenerateAppKey()
+			if err != nil {
+				return fmt.Errorf("new: generate application key: %w", err)
+			}
 			_, err = build.NewApp(ctx, build.NewOptions{
 				Name:      name,
 				Parent:    dir,
 				Framework: framework,
 				NoPlugin:  flagTrue(in, "no-plugin"),
+				AppKey:    key,
+				NoGit:     flagTrue(in, "no-git"),
 			}, out)
 			return err
 		},