Asymmetric quoting/unquoting of object_ids in ModelAdmin urls breaks with CharField primary keys

[LeGast00n]

Problem

The Django admin consistently applies quote() when generating URLs for object_id,
but the inverse unquoting is not applied everywhere during or after URL resolution.

For models with a CharField primary key containing characters such as _,
the ChangeList → Change view object links may break, since the value is escaped in the URL
but not properly decoded on request handling.

Steps to reproduce

1. Define a model with a CharField as the primary key, allowing _ in its values.
2. Register it in the Django admin.
3. Go to the changelist and click the link to a change view.

Observed

• The URL is generated with quote() escaping.
• Resolution fails, e.g. in changelist links, delete view, or custom admin URLs.

Workarounds

• Overriding change_view / delete_view to apply unquoting before calling super() works in some cases.
• For custom admin URLs the problem happens earlier, during URL resolution itself, leaving no straightforward workaround.

Expected

Wherever quote() is used to build admin URLs, the corresponding unquoting
should also be applied consistently during URL resolution, including for custom admin routes.