docs(journal): federation privacy manifest + runbook + honest home blurb (§10)

10.1 Privacy manifest (legal/privacy):
- German legal half: Föderation entry under Empfänger/Drittanbieter —
  what a public profile exposes, what accepted followers' servers
  receive, the loss-of-control over delivered copies, Art. 6(1)(a)
  basis, private profiles don't federate.
- English manifest half: dedicated Federation (ActivityPub) section —
  actor object contents, push delivery + retraction semantics (incl.
  the tombstone caveat), encrypted-at-rest signing keys, remote actor
  cache, ingested remote content with the followers-only viewer gate,
  inbox logging/rate limits. PRIVACY_LAST_UPDATED bumped.

10.2 docs/deployment.md federation runbook: enabling per environment,
key rotation posture, abuse monitoring, and the troubleshooting
checklist distilled from the 2026-06-06/07 soak (IP families first,
no outbox backfill, tombstones, the 10s delivery timeout, actor
re-fetch).

10.3 Home marketing blurb (en+de) aligned to what actually ships:
Mastodon can follow you + trails-to-trails outbound — no more 'follow
friends anywhere' overstatement.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/i18n/src/locales/de.ts

@@ -192,7 +192,7 @@ export default {
         },
         federation: {
           title: "Föderiert by design",
-          body: "Deine Journal-Instanz spricht via ActivityPub mit anderen trails.cool-Servern. Folge Freundinnen und Freunden überall.",
+          body: "Teil des Fediverse via ActivityPub: Mastodon-Nutzer:innen können dir folgen und deine öffentlichen Aktivitäten sehen, und du folgst trails-Nutzer:innen auf jeder Instanz.",
         },
         ownership: {
           title: "Deine Daten, immer",

packages/i18n/src/locales/en.ts

@@ -192,7 +192,7 @@ export default {
         },
         federation: {
           title: "Federated by design",
-          body: "Your Journal instance talks to other trails.cool servers via ActivityPub. Follow friends anywhere.",
+          body: "Part of the fediverse via ActivityPub: Mastodon users can follow you and see your public activities, and you can follow trails users on any instance.",
         },
         ownership: {
           title: "Your data, always",