ADR 0220's dependency mechanism served compiled seats only and retired its one user with
node-resolver-config (commit f68521da). ADR 0378 S8 revives it for module-declared seats:
SeatDeclaration gains Needs, judged by the catalogue check (node scope only, a name that
resolves to a node seat somewhere in the catalogue, never itself), and DependsOn now takes
the catalogue so a claimed seat's needs are found wherever they are declared.
Each contribution grain was a manifest field and a renderer of its own; a module now contributes
to any seat with a kind that seat receives, the holder places it with
${contribution:<seat>:<kind>}, and the contribution depends on the seat. node-hotkeys is the
first new seat to receive (triggers); the display session receives window-manager config.