This update removes unnecessary repeat checks after records are found, reducing extra database work. Users may see slightly faster responses in affected areas such as accounting, appointments, helpdesk, field service, and social integrations, with no expected change in behavior.

Making a `exists()` on a record got by a `search()` is useless and
lead to a extra useless query. Remove them.

This update improves internal testing by making simulated browser environments share one mock server, closer to how multiple tabs work in real use. It helps ensure tests better reflect real-world behavior and reduces inconsistencies when validating multi-tab scenarios.

*: account_accountant, account_invoice_extract, documents, voip, web_studio.

The pyEnv used during tests is based on the mock server to provide
server like api. This issue is that when creating multiple environments
during tests, a new mock server is created each time. This is not realistic
since in a real world scenario, multiple tabs would share a single server.
In order to make pyEnv work with multiple tabs tests (e.g. multiple env tests),
let's create a single mock server shared between js environment during a test.

task-2053917

community: https://github.com/odoo/odoo/pull/97975

This change improves how manufacturing planning finds bill of materials information by caching repeated lookups. It should help planning screens respond more efficiently when working with production data, without changing day-to-day user workflows.