Purge du code de compatibilite jean, base bbolt et arborescence ajean

- suppression des migrations d'agencement, d'unites et de dossier de donnees
- store bbolt unique (ajean.db) : config, prefs, conversation, cles, drapeaux
- arborescence backends/ bin/ presets/ memory/ models/ workspace/
- plus aucune variable, unite ou asset nomme jean

go.sum

@@ -92,6 +92,8 @@ github.com/zeebo/blake3 v0.2.4 h1:KYQPkhpRtcqh0ssGYcKLG1JYvddkEA8QwCM/yBqhaZI=
 github.com/zeebo/blake3 v0.2.4/go.mod h1:7eeQ6d2iXWRGF6npfaxl2CU+xy2Fjo2gxeyZGCRUjcE=
 github.com/zeebo/pcg v1.0.1 h1:lyqfGeWiv4ahac6ttHs+I5hwtH/+1mrhlCtVNQM2kHo=
 github.com/zeebo/pcg v1.0.1/go.mod h1:09F0S9iiKrwn9rlI5yjLkmrug154/YRW6KnnXVDM/l4=
+go.etcd.io/bbolt v1.5.0 h1:S7GAl7Fxv12yohbwFfIbQCGDWbQbtDGPET4P/bD4lxU=
+go.etcd.io/bbolt v1.5.0/go.mod h1:mkltfYE5aUHQxUct9N9V+Kp7aSjFqjgrhcXIS70Lrdk=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=