feat: publication management with cover images, PDFs, and fruit images (story #04)

Full CRUD for publications; link fruits to publications; upload per-fruit
PDF descriptions and fruit images stored as BYTEA; fruit detail page shows
publication descriptions and images. ImageOverlayDrawer for cover thumbnail
full-size view.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/cmd/server/router.go

@@ -41,5 +41,34 @@ func New(pool *pgxpool.Pool) *echo.Echo {
 	g.GET("/:id/images/:imageId", fruits.ServeImage)
 	g.DELETE("/:id/images/:imageId", fruits.DeleteImage)
 
+	// Publications (story #04)
+	pubRepo := repository.NewPublicationRepo(pool)
+	pubs := handler.NewPublicationHandler(pubRepo)
+
+	// Fruit-scoped publication reads
+	g.GET("/:id/descriptions", pubs.GetFruitDescriptions)
+	g.GET("/:id/publication-images", pubs.GetFruitPublicationImages)
+
+	p := api.Group("/publications")
+	p.GET("", pubs.List)
+	p.POST("", pubs.Create)
+	p.GET("/:id", pubs.Get)
+	p.PUT("/:id", pubs.Update)
+	p.DELETE("/:id", pubs.Delete)
+	p.POST("/:id/image", pubs.UploadCoverImage, middleware.BodyLimit("5M"))
+	p.GET("/:id/image", pubs.ServeCoverImage)
+	p.DELETE("/:id/image", pubs.DeleteCoverImage)
+	p.GET("/:id/fruits", pubs.ListFruits)
+	p.POST("/:id/fruits", pubs.LinkFruit)
+	p.DELETE("/:id/fruits/:fruitId", pubs.UnlinkFruit)
+	p.GET("/:id/descriptions", pubs.ListDescriptions)
+	p.POST("/:id/descriptions", pubs.UploadDescription, middleware.BodyLimit("5M"))
+	p.GET("/:id/descriptions/:descId", pubs.ServeDescription)
+	p.DELETE("/:id/descriptions/:descId", pubs.DeleteDescription)
+	p.GET("/:id/fruit-images", pubs.ListFruitImages)
+	p.POST("/:id/fruit-images", pubs.UploadFruitImage, middleware.BodyLimit("5M"))
+	p.GET("/:id/fruit-images/:imgId", pubs.ServeFruitImage)
+	p.DELETE("/:id/fruit-images/:imgId", pubs.DeleteFruitImage)
+
 	return e
 }