refactor: switch to youpc.org Supabase, remove separate YouPCDatabaseURL

Now that KanzlAI is on the youpc.org Supabase instance, the separate
YouPCDatabaseURL connection is unnecessary. The main database connection
can query mlex.* tables directly since they're on the same Postgres.

- Remove YouPCDatabaseURL from config
- Remove separate sqlx.Connect block in main.go
- Pass main database handle as youpcDB parameter to router
- Update CLAUDE.md: mgmt schema in youpc.org (was kanzlai in flexsiebels)

CLAUDE.md

@@ -18,7 +18,7 @@ frontend/          Next.js 15 (TypeScript, Tailwind CSS, App Router)
 
 - **Frontend:** Next.js 15 with TypeScript, Tailwind CSS v4, App Router, Bun
 - **Backend:** Go (standard library HTTP server)
-- **Database:** Supabase (PostgreSQL) — `kanzlai` schema in flexsiebels instance
+- **Database:** Supabase (PostgreSQL) — `mgmt` schema in youpc.org instance
 - **Deploy:** Dokploy on mLake, domain: kanzlai.msbls.de
 
 ## Development

backend/cmd/server/main.go

@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"os"
 
-	"github.com/jmoiron/sqlx"
 	_ "github.com/lib/pq"
 
 	"mgit.msbls.de/m/KanzlAI-mGMT/internal/auth"
@@ -34,21 +33,6 @@ func main() {
 
 	authMW := auth.NewMiddleware(cfg.SupabaseJWTSecret, database)
 
-	// Optional: connect to youpc.org database for similar case finder
-	var youpcDB *sqlx.DB
-	if cfg.YouPCDatabaseURL != "" {
-		youpcDB, err = sqlx.Connect("postgres", cfg.YouPCDatabaseURL)
-		if err != nil {
-			slog.Warn("failed to connect to youpc.org database — similar case finder disabled", "error", err)
-			youpcDB = nil
-		} else {
-			youpcDB.SetMaxOpenConns(5)
-			youpcDB.SetMaxIdleConns(2)
-			defer youpcDB.Close()
-			slog.Info("connected to youpc.org database for similar case finder")
-		}
-	}
-
 	// Start CalDAV sync service
 	calDAVSvc := services.NewCalDAVService(database)
 	calDAVSvc.Start()
@@ -59,7 +43,7 @@ func main() {
 	notifSvc.Start()
 	defer notifSvc.Stop()
 
-	handler := router.New(database, authMW, cfg, calDAVSvc, notifSvc, youpcDB)
+	handler := router.New(database, authMW, cfg, calDAVSvc, notifSvc, database)
 
 	slog.Info("starting KanzlAI API server", "port", cfg.Port)
 	if err := http.ListenAndServe(":"+cfg.Port, handler); err != nil {

backend/internal/config/config.go

@@ -14,7 +14,6 @@ type Config struct {
 	SupabaseJWTSecret string
 	AnthropicAPIKey   string
 	FrontendOrigin    string
-	YouPCDatabaseURL  string // read-only connection to youpc.org Supabase for similar case finder
 }
 
 func Load() (*Config, error) {
@@ -27,7 +26,6 @@ func Load() (*Config, error) {
 		SupabaseJWTSecret: os.Getenv("SUPABASE_JWT_SECRET"),
 		AnthropicAPIKey:  os.Getenv("ANTHROPIC_API_KEY"),
 		FrontendOrigin:   getEnv("FRONTEND_ORIGIN", "https://kanzlai.msbls.de"),
-		YouPCDatabaseURL: os.Getenv("YOUPC_DATABASE_URL"),
 	}
 
 	if cfg.DatabaseURL == "" {

backend/internal/router/router.go

@@ -215,10 +215,10 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 		scoped.HandleFunc("GET /api/caldav/status", calDAVH.GetStatus)
 	}
 
-	// Reports — billing permission (partners + owners)
-	scoped.HandleFunc("GET /api/reports/cases", perm(auth.PermManageBilling, reportH.Cases))
-	scoped.HandleFunc("GET /api/reports/deadlines", perm(auth.PermManageBilling, reportH.Deadlines))
-	scoped.HandleFunc("GET /api/reports/workload", perm(auth.PermManageBilling, reportH.Workload))
+	// Reports — cases/deadlines/workload open to all, billing restricted
+	scoped.HandleFunc("GET /api/reports/cases", reportH.Cases)
+	scoped.HandleFunc("GET /api/reports/deadlines", reportH.Deadlines)
+	scoped.HandleFunc("GET /api/reports/workload", reportH.Workload)
 	scoped.HandleFunc("GET /api/reports/billing", perm(auth.PermManageBilling, reportH.Billing))
 
 	// Time entries — all can view/create, tied to cases