Odoo Release Updates

[FIX] sign: use unique item roles for demo templates

[IMP] test_lint{,_enterprise}, *: Index `Many2one` fields in `related` fields

[FIX] sign: preserve PDF structure when adding signature overlays

[FIX] sign: prevent UI break when roles have 'assign to' set

[REF] various: remove useless 'tracking_disable' / 'mail_notrack' in tests

[FIX] sign: prevent crash when fetching deleted sign request

[FIX] sign: fix certificate accuracy and Sign Now flows, and confirmation email

[FIX] sign: incorrect document download lookup

[IMP] sign: add two-way sync for linked fields

[FIX] sign: use datepicker format when auto-filling date fields

[REF] *: run rendering context migration script on inline xml

[IMP] whatsapp_sign: enable multi-company WhatsApp support and template configuration

[FIX] sign: enforce required fields for signature roles in server actions

[FIX] sign: enhance templates UI, request flows, and fix dialog bugs

[FIX] sign: hide "Details" button in signing mode

[FIX] sign: perform check before comparing types

[FIX] sign: stop cancelling fully signed documents

[IMP] sign: mail alias should throw error

[FIX] sign: resolve access error for shared custom fields in templates

[IMP] *: replace `@api.onchange` with `@api.depends` for non-stored computed fields

[IMP] sign: portal view improvements

[FIX] sign: handle base64 strings in pdf validation

[IMP] sign: align signature buttons in activity popover

[REF] sign: move signature request logic to Activity model

[IMP] sign: allow viewing canceled signature requests in portal

[FIX] sign: sync PDF viewer theme with Odoo color scheme

[FIX] sign: Restore sign Item placeholder initialization

[FIX] sign: Align sign now wizard with send request

[FIX] sign: signing dialog

[FIX] sign: remove undeterministicTour key