Completes the design record on main: Plan B's plan and the federation spec were
already here; this adds the umbrella security spec (source of truth for the
remaining container/web/desktop/remediation workstreams) and Plan A's plan.
routes/federation.ts had grown to 7.6k lines, spanning HTTP route
registration, federated identity resolution, ~30 inbound relay event
processors, DM reconciliation, and rate-limiting internals — too large
to review or hold in context, and awkward to change safely.
Split the implementation into 18 focused modules under routes/federation/
(helpers, events/, handlers/) and keep routes/federation.ts as a thin
barrel that re-exports the public API and composes the HTTP registrars
into federationRoutes(). No import paths change anywhere else.
Pure move, no behavior change:
- 61/61 named functions byte-identical; only deltas are 2 dynamic-import
paths adjusted for the new directory depth
- public export surface unchanged (barrel re-exports all 22 symbols)
- all 30 endpoints preserved (identical verb+path set)
- typecheck, build, and full server suite (790 tests) green
Docs: update federation.md source-file map; add split design doc.