Add shared Manifest UI for delivery, quote, and order.

Wire quote/order API clients and routes, then unify list/create/edit behind ManifestList/Form tiles so Lieferungen and Auftrag share one stack.

src/pages/kunde/neu.jsx

@@ -148,25 +148,21 @@ class KundeNeuPage extends PureComponent {
               getOptionLabel={(option) => String(option.name ?? '')}
               isOptionEqualToValue={(option, value) => option.id === value.id}
               onChange={this.handleGroupChange}
-              renderInput={(params) => {
-                const { InputProps, inputProps, ...other } = params;
-                return (
-                  <TextField
-                    {...other}
-                    label="Kundengruppe"
-                    required
-                    autoComplete="off"
-                    slotProps={{
-                      input: InputProps,
-                      htmlInput: {
-                        ...inputProps,
-                        spellCheck: false,
-                        autoComplete: 'off',
-                      },
-                    }}
-                  />
-                );
-              }}
+              renderInput={(params) => (
+                <TextField
+                  {...params}
+                  label="Kundengruppe"
+                  required
+                  slotProps={{
+                    ...params.slotProps,
+                    htmlInput: {
+                      ...params.slotProps?.htmlInput,
+                      spellCheck: false,
+                      autoComplete: 'off',
+                    },
+                  }}
+                />
+              )}
             />
             <SingleLineTextEdit
               size="small"