Add random password generation for new users

- Move GenerateRandomPassword to auth package for reuse
- Make password optional in user creation (generates 16-char if empty)
- Return generated password in response for user to copy
- Add Generate/Copy UI with show/hide toggle

backend/internal/api/handlers/users.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 
+	"git.workaround.org/chaas/imc/backend/internal/auth"
 	"git.workaround.org/chaas/imc/backend/internal/db"
 	"git.workaround.org/chaas/imc/backend/internal/mail"
 	"github.com/gin-gonic/gin"
@@ -22,7 +23,7 @@ func NewUserHandler(database *db.DB) *UserHandler {
 
 type CreateUserRequest struct {
 	Email    string `json:"email" binding:"required"`
-	Password string `json:"password" binding:"required"`
+	Password string `json:"password"`
 	Quota    int64  `json:"quota"`
 }
 
@@ -169,7 +170,11 @@ func (h *UserHandler) Create(c *gin.Context) {
 		return
 	}
 
-	passwordHash := "{BLF-CRYPT}" + req.Password
+	password := req.Password
+	if password == "" {
+		password = auth.GenerateRandomPassword(16)
+	}
+	passwordHash := "{BLF-CRYPT}" + password
 
 	err = h.db.CreateUser(ctx, domain.ID, req.Email, passwordHash, req.Quota)
 	if err != nil {
@@ -178,7 +183,7 @@ func (h *UserHandler) Create(c *gin.Context) {
 		return
 	}
 
-	Created(c, map[string]string{"message": "user created"})
+	Created(c, map[string]interface{}{"message": "user created", "password": password})
 }
 
 func (h *UserHandler) Update(c *gin.Context) {