feat: manage fruits — full CRUD with images and synonyms (story #02)

Backend: domain structs, FruitRepository interface + pg implementation,
9 Echo v4 handlers (list/get/create/update/delete, image sub-resources),
migration 000002 (fruit_type ENUM, fruits, fruit_synonyms, fruit_images),
route-scoped BodyLimit("5M") for uploads, http.DetectContentType for serving.

Frontend: typed fetch API layer, Pinia setup-style fruitStore, FruitList
(paginated), FruitCreate, and FruitDetail (edit + synonyms editor + image
gallery). 25 backend unit tests + integration test; 18 frontend tests.

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

backend/cmd/server/router.go

@@ -6,30 +6,17 @@ import (
 	"github.com/labstack/echo/v4/middleware"
 
 	"osdb/internal/handler"
+	"osdb/internal/repository"
 )
 
 // New creates and configures the Echo instance with all routes registered.
-// pool is stored on Echo's context so all handlers added by future stories
-// (#2 fruits, #4 publications, #7 thumbnails, #8 auth) can retrieve it via
-// c.Get("pool").(*pgxpool.Pool).
-//
-// Extension point: story #2, #4, #7, #8 route groups are added here.
 func New(pool *pgxpool.Pool) *echo.Echo {
 	e := echo.New()
 	e.HideBanner = true
 
-	// Global middleware
 	e.Use(middleware.Logger())
 	e.Use(middleware.Recover())
 
-	// Make pool available to all handlers via Echo context.
-	e.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
-		return func(c echo.Context) error {
-			c.Set("pool", pool)
-			return next(c)
-		}
-	})
-
 	health := handler.NewHealthHandler()
 
 	// Root health — used by docker healthcheck + ops tooling
@@ -39,7 +26,20 @@ func New(pool *pgxpool.Pool) *echo.Echo {
 	api := e.Group("/api/v1")
 	api.GET("/health", health.Health)
 
-	// Future story groups (fruits, publications, admin, auth) are added here.
+	// Fruits (story #02)
+	fruitRepo := repository.NewFruitRepo(pool)
+	fruits := handler.NewFruitHandler(fruitRepo)
+
+	g := api.Group("/fruits")
+	g.GET("", fruits.List)
+	g.POST("", fruits.Create)
+	g.GET("/:id", fruits.Get)
+	g.PUT("/:id", fruits.Update)
+	g.DELETE("/:id", fruits.Delete)
+	g.GET("/:id/images", fruits.ListImages)
+	g.POST("/:id/images", fruits.UploadImage, middleware.BodyLimit("5M"))
+	g.GET("/:id/images/:imageId", fruits.ServeImage)
+	g.DELETE("/:id/images/:imageId", fruits.DeleteImage)
 
 	return e
 }