Add Kunde CRUD with addresses/contacts, delivery edit, and Auftrag sub-nav.

Wire customergroup/entity APIs, Lieferungen detail editing, and Angebot/Bestellung/Ausliefern/Retoure placeholders.

src/pages/lieferung/neu.jsx

@@ -187,7 +187,7 @@ class LieferungNeuPage extends PureComponent {
       await this.context.updateDelivery();
       if (this._cancelled) return;
       enqueueSnackbar('Lieferung angelegt.', { variant: 'success' });
-      void router.navigate('/lieferung');
+      void router.navigate(`/lieferung/${data.delivery.id}`);
     } catch (err) {
       if (this._cancelled) return;
       notifyError(err);
@@ -236,18 +236,24 @@ class LieferungNeuPage extends PureComponent {
             isOptionEqualToValue={(option, value) => option.id === value.id}
             onChange={this.handleSupplierChange}
             sx={{ flex: 1, minWidth: 220 }}
-            renderInput={(params) => (
-              <TextField
-                {...params}
-                label="Lieferant"
-                autoComplete="off"
-                inputProps={{
-                  ...params.inputProps,
-                  spellCheck: false,
-                  autoComplete: 'off',
-                }}
-              />
-            )}
+            renderInput={(params) => {
+              const { InputProps, inputProps, ...other } = params;
+              return (
+                <TextField
+                  {...other}
+                  label="Lieferant"
+                  autoComplete="off"
+                  slotProps={{
+                    input: InputProps,
+                    htmlInput: {
+                      ...inputProps,
+                      spellCheck: false,
+                      autoComplete: 'off',
+                    },
+                  }}
+                />
+              );
+            }}
           />
           <SingleLineTextEdit
             size="small"