fix: make the label screen work in the default-twig back office

[mabruchet]

Problem

On a Thelia 3 shop with the default-twig back office, the label generator of the order page does nothing:

1. order-edit-js.html.twig inserts the label table into #bill. In default-twig the invoicing pane is #tab-bill, so the table and the "Generate new label" button never appear.
2. The inline script calls bootstrap.Modal.getOrCreateInstance() while the page is still being parsed. In default-twig Bootstrap is exposed by a deferred module, so the script stops with bootstrap is not defined before the click handlers are bound.
3. When the generation fails (WSDL unreachable, bad credentials, a SOAP fault), OrderController::generateLabelAction() redirects to the label list. The modal expects JSON (json.error), parses the HTML of the redirect and shows SyntaxError: Unexpected token '<'.

The same SOAP failure on /admin/module/ColissimoLabel/bordereau/generate is not caught and ends as a 500.

Changes

• order-edit-js.html.twig: look for #tab-bill first and fall back to #bill; run the script on DOMContentLoaded.
• OrderController: with ?edit-order=1, a failure returns {"error": "<message>"} with a 500 status instead of a redirect. The label page keeps its redirect and its error context.
• BordereauController: a SoapFault is shown on the bordereau list like the other errors of that page.

How to check

On a base where the endpoint of the module points to an address that never answers (for example https://example.invalid/ws?wsdl):

1. Open an order shipped by Colissimo, tab "Invoicing and delivery": the label table and both buttons are there.
2. "Generate new label", enter a weight, print: the modal shows SOAP-ERROR: Parsing WSDL: Couldn't load from ..., the response is application/json with status 500, and no row is added to colissimo_label.
3. /admin/module/ColissimoLabel/bordereau/generate shows the same message in the page.

Checked in a browser on Thelia 3.2 / default-twig. No change to the SOAP request, the stored data or the configuration keys.

Not covered

The default (Smarty) templates are untouched. A successful generation against the real service was not run.