refactor(services): rename Go services, remove -go suffix

mana-search-go → mana-search
mana-notify-go → mana-notify
mana-crawler-go → mana-crawler
mana-api-gateway-go → mana-api-gateway

Legacy NestJS versions are deleted, suffix no longer needed.
Updated all references in docker-compose, CLAUDE.md, package.json,
Forgejo workflows, and service package.json files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

services/mana-notify/internal/handler/common.go

@@ -0,0 +1,24 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+	"time"
+)
+
+func writeJSON(w http.ResponseWriter, status int, data any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(data)
+}
+
+func writeError(w http.ResponseWriter, status int, message string) {
+	writeJSON(w, status, map[string]any{
+		"success": false,
+		"error": map[string]any{
+			"statusCode": status,
+			"message":    message,
+			"timestamp":  time.Now().UTC().Format(time.RFC3339),
+		},
+	})
+}