Image processing now caps JPEG quality at a level where higher values no longer improve visible results. This helps avoid unnecessarily large image files while preserving image quality for users.

Values above 95 do not increase the quality but they disable optimizations that
increase the file size unnecessarily.

See `quality` parameter at
https://pillow.readthedocs.io/en/4.0.x/handbook/image-file-formats.html#jpeg

Part of task-1930726

Adds a shared helper that converts selected files or images into a format the system can preview or send directly. This reduces duplicated handling across several Odoo apps and supports smoother image previews and uploads without relying on traditional form submissions.

This can be used for example to preview an image from a file input field.

It can also be used to send the base64 content of the input by RPC instead of
having to rely on form submit as POST with multipart/form-data.

Technically wrap FileReader.readAsDataURL in a Promise.

This will also be used in task-1930726

The search panel now displays category values in the same order provided by the server. This keeps lists predictable for users and avoids confusing reordering in views such as kanban.

After this commit, the order of the elements of the search panel
categories follow the original order received from the back-end.

Task: #1972698

This update standardizes how files are read in Documents, salary contracts, and Sign workflows. It should make file upload and preview behavior more consistent for users while keeping the visible experience largely unchanged.

Enterprise counterpart of https://github.com/odoo/odoo/pull/33508