fix(auth): return JSON for HTMX login failures instead of HTML

internal/handlers/auth.go

@@ -332,7 +332,7 @@ func (h *AuthHandler) Login(c echo.Context) error {
 		}
 
 		if c.Request().Header.Get("HX-Request") == "true" {
-			return c.HTML(http.StatusUnauthorized, `<div class="text-red-500">Invalid credentials</div>`)
+			return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
 		}
 		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
 	}
@@ -348,7 +348,7 @@ func (h *AuthHandler) Login(c echo.Context) error {
 		}
 
 		if c.Request().Header.Get("HX-Request") == "true" {
-			return c.HTML(http.StatusUnauthorized, `<div class="text-red-500">Invalid credentials</div>`)
+			return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
 		}
 		return c.JSON(http.StatusUnauthorized, map[string]string{"error": "invalid credentials"})
 	}