Add `exposeNestedServerSecrets()` to Applications, Databases, and
Services controllers so that `read:sensitive`/`root` tokens see
sentinel and logdrain fields on eager-loaded Server + ServerSetting
relations.
ServicesController handles both single models and Eloquent Collections
(listing endpoint passes a Collection per project).
Tests tightened to use JSON-key assertions (`"field":`) to avoid false
positives from field names appearing in values.
Models now declare $hidden for passwords, tokens, db URLs, and compose
fields. API controllers flip from makeHidden-on-deny to makeVisible-on-
allow (can_read_sensitive=true), fixing fields that were never hidden.
Also adds missing fields (mysql/mariadb passwords, logdrain keys, etc.)
to privileged disclosure lists.
Tests added: Feature/Security/ApiSensitiveFieldsTest and
Unit/Models/SensitiveFieldsHiddenTest cover all affected models and
controllers.
Andras Bacsai