Steps to reproduce:
- send an image in a Discuss channel
- click the image to open the file viewer
- click the download button

=> Android shows "The Odoo Mobile Apps only supports file downloads
   using the HTTP protocol."

downloadFile()'s GET-by-URL case fetches the URL via XHR, then saves the Blob response by clicking a hidden <a download> anchor on a blob: URL. Android's DownloadManager only accepts http(s) URLs, so it rejects that blob: URL instead of downloading anything.

Patch downloadFile._download to hand the URL directly to a new mobile.methods.saveFile bridge method when available, the same way download._download already delegates to mobile.methods.downloadFile.

Blob/string content downloads aren't handled here — the only such call site (spreadsheet JSON export) is debug-mode only, so this is left as a console.warn for now.

Related to odoo/odoo@e83fd8c08c879f5e262d39f24edcb3f81238ea82

Code made by Claude
Changes supervised by HUVW

Forward-Port-Of: odoo/enterprise#127693

### Steps to Reproduce:
1). Install l10n_vn_edi_viettel ('Vietnam E-Invoicing') module in v18. 
2). Migrate the database in any version above v18. 
3). AccessError will appear while generating ('Send to SInvoice') on invoice for non-admin users.

### Issue:
- In v18, users were able to send and generate documents via (Send to SInvoice). Since v18.1 onwards, field access [check] is enforced during this flow, and since `l10n_vn_edi_username` is restricted to admin users only [here], non-admin users hit an AccessError as soon as
`_l10n_vn_edi_get_credentials_company` reads this field on`res.company`.

```py
You do not have enough rights to access the field "l10n_vn_edi_username" on Companies (res.company). Please contact your system administrator.

Operation: read
User: 12
Groups: allowed for groups 'Role / Administrator'
```

### Solution:
- This commit fixes the issue by adding a `sudo()` call on the company inside [_l10n_vn_edi_get_credentials_company] itself, so that non-admin users can successfully send and generate documents like in the previous version, without any hassle.

[check]: https://github.com/odoo/odoo/blob/5ca10578a2fd1b40cd371ed5ad20c1654dfe54d3/odoo/orm/models.py#L3384
[here]: https://github.com/odoo/odoo/blob/5ca10578a2fd1b40cd371ed5ad20c1654dfe54d3/addons/l10n_vn_edi_viettel/models/res_company.py#L9
[_l10n_vn_edi_get_credentials_company]: https://github.com/odoo/odoo/blob/ecc267a231958c2dd99a7287c6bd1adbdbd22965/addons/l10n_vn_edi_viettel/models/account_move.py#L885

Ticket [link](https://www.odoo.com/odoo/project.task/6434854)
opw-6434854

### Issue before this commit:
When using the "Reverse and Create Invoice" feature on a posted invoice with a foreign currency and Cash Basis enabled, the expected Exchange Difference and Cash Basis tax entries are not generated upon the automatic reconciliation. The credit note is successfully created and reconciled with the original invoice, but the P&L exchange difference and the cash basis transition lines are completely missing. Currently, the only workaround is to manually reset the generated credit note to draft and re-post it, which forces the system to correctly calculate the currency rate differences and generate the missing entries.

### Steps to reproduce the issue:
1. Download Accounting
2. Go to Settings > Cash basis. Tick it and set as 'Base Tax Received Account' an account like 201000 Current Liabilities
3. Go to Chart of Accounts > search your account (ex. 201000 Current Liabilities) and be sure the flag of 'Allow Reconciliation' is on
4. Go to Taxes > 15% sales > set 'Tax Exigibility' as Based on Payment and 'Cash Basis Transition Account' always as 201000 Current Liabilities
5. Go to Currencies and set a new currency like MXN inserting tax rates as:
	1. 1 july 2026: 20$
	2. 15 july 2026: 15$
6. Create a new invoice with price 100 and 15% tax, set MXN as currency for the journal, set the date as 1 july and confirm it
7. Click on 'Credit Note', then 'Reverse and Create Invoice' and confirm it
8. go back to the invoice and see that after the total amount there is a new line 'Reversed on...'
9. After that line there should also be the line with the Exchange Difference since the tax rates for MXN currency were different at the moment of the invoice and at the moment of the credit note. This is only created by resetting to draft the credit note and confirm it again.

### Cause of the issue:
In the account.move.reversal wizard, when is_modify = True (Reverse and Create), the system triggers _reverse_moves with cancel=True. At the end of the _reverse_moves method, the newly created reverse moves are automatically posted and reconciled. However, this automatic posting is executed with move_reverse_cancel=True injected into the context: reverse_moves.with_context(move_reverse_cancel=cancel)._post(soft=False). When the reconciliation engine (_reconcile_plan_with_sync and _create_exchange_difference_moves) detects this specific context key, it intentionally bypasses the creation of both the exchange difference P&L moves and the cash basis entries, treating the reversal as a pure administrative cancellation rather than a financial operation with currency fluctuations.

### Reason to introduce the fix:
To ensure financial accuracy and compliance, especially when cash basis and multi-currency are involved, a reversal on a different date must reflect the actual exchange rate fluctuations and properly trigger cash basis rules. By removing the move_reverse_cancel context injection during the automatic posting of the reverse moves, we allow the native reconciliation engine to evaluate the newly computed balance (based on the credit note's date) against the original invoice. This ensures that exchange differences and cash basis journal entries are automatically and accurately generated on the first attempt.

opw-6399867

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