mara, PR review: "make agentspage a subdir now that its split into
sub components". AgentsPage.tsx/.css, AgentCard.tsx/.css,
AgentTypes.ts, and WantedMenu.tsx move as a family into their own
pages/agents/ directory; CreateAgentForm and LinkMatrixAccountForm
stay in pages/ since they aren't part of this split (CreateAgentForm
is still rendered inside AgentsPage's own dialog but is a standalone,
independently-named form, not one of the pieces carved out of the
page itself).
Pure move: relative imports within the new pages/agents/ family are
unchanged (they were always siblings), only the ones reaching back
out to ui/ and the two forms above gained one more '../', plus
App.tsx's route import.