Requester-facing read-only detail view for a process instance

Opening a request from the My requests list now leads to a requester-facing, read-only detail view of that one process instance, in the requester's own language and with none of the operator trace.

The detail at /orchestra/my-instances/{instance} shows:

• a header: workflow label, reference, created date, current status and current step;
• a Progress timeline of the statuses the request has passed through, derived from the instance's token history mapped through the status vocabulary (no new storage, no optional module), oldest first with the current one flagged;
• the data the requester submitted, rendered through a neutral orchestra.instance_source seam that mirrors the status collector: a webform provider ships here, a booking provider ships in yoyaku.

The route is gated by the View own process instances permission plus an initiator-ownership access check, so a requester reads only their own request and, unlike the admin instance routes, a full administrator does not bypass that ownership.

Path swap (pre-1.0, generic naming): the orchestra_ui requester surface moves to /orchestra/my-instances, and the orchestra_views "My workflow instances" list to /orchestra/my-requests, whose Reference column now links to the detail view.

Kernel and functional tests cover the timeline derivation, the initiator access check, the detail render (no admin sections) and the card link. Docs and French translations updated.