feat(04-01): scaffold Winter-shaped plugins with generated registry

Render plugin.go, routes.go, leaf packages and go.mod from embedded
templates, emit empty registry accessors, and define job, admin, lang
and mail capability contracts so a new plugin compiles before artifacts.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/build/stubs/plugin.tmpl

@@ -0,0 +1,109 @@
+{{define "plugin.go"}}package {{.Package}}
+
+import (
+	"embed"
+	"io/fs"
+
+	"git.golem15.com/golem15/summercms/backpack"
+	"git.golem15.com/golem15/summercms/bonfire"
+	"git.golem15.com/golem15/summercms/pact"
+	"git.golem15.com/golem15/summercms/party"
+	"github.com/go-gormigrate/gormigrate/v2"
+)
+
+var (
+	_ pact.HasConfig           = (*Plugin)(nil)
+	_ pact.HasLang             = (*Plugin)(nil)
+	_ pact.HasMailTemplates    = (*Plugin)(nil)
+	_ pact.HasModels           = (*Plugin)(nil)
+	_ pact.HasMigrations       = (*Plugin)(nil)
+	_ pact.HasCommands         = (*Plugin)(nil)
+	_ pact.HasJobs             = (*Plugin)(nil)
+	_ pact.HasAdminControllers = (*Plugin)(nil)
+)
+
+//go:embed config
+var configFS embed.FS
+
+//go:embed lang
+var langFS embed.FS
+
+//go:embed views/mail
+var mailFS embed.FS
+
+// Plugin is the {{.ID}} plugin.
+type Plugin struct{}
+
+func (p *Plugin) ID() string         { return {{printf "%q" .ID}} }
+func (p *Plugin) Requires() []string { return nil }
+
+func (p *Plugin) Register(*backpack.App) error { return nil }
+func (p *Plugin) Boot(*backpack.App) error     { return nil }
+
+func (p *Plugin) ConfigFS() fs.FS { return configFS }
+func (p *Plugin) LangFS() fs.FS   { return langFS }
+
+func (p *Plugin) MailTemplatesFS() fs.FS         { return mailFS }
+func (p *Plugin) MailTemplates() []string        { return nil }
+func (p *Plugin) MailLayouts() map[string]string { return nil }
+
+func (p *Plugin) Models() []any                         { return generatedModels() }
+func (p *Plugin) Migrations() []*gormigrate.Migration   { return generatedMigrations() }
+func (p *Plugin) Commands() []bonfire.Command           { return generatedCommands() }
+func (p *Plugin) Jobs() []pact.Job                      { return generatedJobs() }
+func (p *Plugin) AdminControllers() []pact.AdminController {
+	return generatedAdminControllers()
+}
+
+func init() {
+	party.Register(&Plugin{})
+}
+{{end}}
+
+{{define "routes.go"}}package {{.Package}}
+
+import "git.golem15.com/golem15/summercms/pact"
+
+var _ pact.HasRoutes = (*Plugin)(nil)
+
+func (p *Plugin) Routes(pact.Router) error { return nil }
+{{end}}
+
+{{define "go.mod"}}module {{.Module}}
+
+{{.GoVersion}}
+
+{{.Toolchain}}
+
+require {{.Framework}} v0.0.0
+{{if .Replace}}
+replace {{.Framework}} => {{.Replace}}
+{{end}}{{end}}
+
+{{define "models/doc.go"}}// Package models holds GORM models for the {{.ID}} plugin.
+package models
+{{end}}
+
+{{define "classes/doc.go"}}// Package classes holds services and hooks for the {{.ID}} plugin.
+package classes
+{{end}}
+
+{{define "controllers/doc.go"}}// Package controllers holds HTTP handlers and admin controllers for the {{.ID}} plugin.
+package controllers
+{{end}}
+
+{{define "console/doc.go"}}// Package console holds bonfire commands for the {{.ID}} plugin.
+package console
+{{end}}
+
+{{define "jobs/doc.go"}}// Package jobs holds background jobs for the {{.ID}} plugin.
+package jobs
+{{end}}
+
+{{define "middleware/doc.go"}}// Package middleware holds named HTTP middleware for the {{.ID}} plugin.
+package middleware
+{{end}}
+
+{{define "updates/doc.go"}}// Package updates holds the gormigrate set for the {{.ID}} plugin.
+package updates
+{{end}}

internal/build/stubs/registry.tmpl

@@ -0,0 +1,73 @@
+{{define "registry.go"}}// Code generated by summer make. DO NOT EDIT.
+
+package {{.Package}}
+
+import (
+	"git.golem15.com/golem15/summercms/bonfire"
+	"git.golem15.com/golem15/summercms/pact"
+	"github.com/go-gormigrate/gormigrate/v2"
+{{- range .Imports}}
+	{{printf "%q" .}}
+{{- end}}
+)
+
+func generatedModels() []any {
+{{- if .Models}}
+	return []any{
+	{{- range .Models}}
+		&{{.Package}}.{{.Ident}}{},
+	{{- end}}
+	}
+{{- else}}
+	return nil
+{{- end}}
+}
+
+func generatedMigrations() []*gormigrate.Migration {
+{{- if .Migrations}}
+	return []*gormigrate.Migration{
+	{{- range .Migrations}}
+		{{.Package}}.{{.Ident}}(),
+	{{- end}}
+	}
+{{- else}}
+	return nil
+{{- end}}
+}
+
+func generatedCommands() []bonfire.Command {
+{{- if .Commands}}
+	return []bonfire.Command{
+	{{- range .Commands}}
+		{{.Package}}.{{.Ident}}(),
+	{{- end}}
+	}
+{{- else}}
+	return nil
+{{- end}}
+}
+
+func generatedJobs() []pact.Job {
+{{- if .Jobs}}
+	return []pact.Job{
+	{{- range .Jobs}}
+		{{.Package}}.{{.Ident}}(),
+	{{- end}}
+	}
+{{- else}}
+	return nil
+{{- end}}
+}
+
+func generatedAdminControllers() []pact.AdminController {
+{{- if .AdminControllers}}
+	return []pact.AdminController{
+	{{- range .AdminControllers}}
+		{{.Package}}.{{.Ident}}(),
+	{{- end}}
+	}
+{{- else}}
+	return nil
+{{- end}}
+}
+{{end}}