Rebuild the Journal home around a public feed and flagship marketing

The old home was an h1, subtitle, and two auth buttons — visitors
arriving at trails.cool had no idea what it was, and self-hosted
instances had nothing interesting to land on.

The new home is one layout that serves both audiences:

- Hero: a product-describing h1 ("Federated outdoor journal") +
  tagline. The site name already lives in the top banner and nav brand,
  so the h1 carries the pitch instead of triplicating "trails.cool".
- Auth CTAs: Register (blue) + Sign In (outlined) get primary weight.
  Planner demotes to a small "Or try the Planner without an account →"
  link below them — it's a nice escape hatch but not the goal.
- Marketing cards: on the flagship only, a 2x2 grid of emoji-icon cards
  for Planner / Journal / Federation / Ownership, matching the Planner
  home's visual weight. `IS_FLAGSHIP=true` toggles it. Self-hosters get
  a "Powered by trails.cool — about the project" link back to the
  flagship instead, so they don't have to write their own marketing.
- Public feed: reverse-chronological list of the 20 most recent public
  activities on the instance, with owner + distance + date. Empty state
  for fresh installs.

Plumbing:
- `listRecentPublicActivities(limit)` in activities.server.ts joins
  users so the feed can render "by <displayName>" in one query.
- `IS_FLAGSHIP` env wired through docker-compose.yml; cd-apps and
  cd-infra both write `IS_FLAGSHIP=true` alongside `DOMAIN=trails.cool`,
  so self-hosters (who deploy without these workflows) default to off.

Specs:
- `activity-feed`: new "Instance-wide public activity feed" requirement
  so the visibility contract is pinned (public in feed, unlisted +
  private are not).
- `journal-landing`: new small spec capturing the hero / marketing /
  feed layout contract and the `IS_FLAGSHIP` toggle, so future
  instance-branding or empty-state changes have a stable anchor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/i18n/src/locales/de.ts

@@ -162,6 +162,36 @@ export default {
     passkeyAdded: "Passkey hinzugefügt! Du kannst dich jetzt sofort auf diesem Gerät anmelden.",
     passkeyStatus: "{{count}} Passkey registriert",
     passkeyStatus_other: "{{count}} Passkeys registriert",
+    home: {
+      heroTitle: "Föderiertes Outdoor-Tagebuch",
+      heroSubtitle: "Plane Routen, halte Aktivitäten fest, behalte deine Daten.",
+      tryPlannerPrefix: "Oder ",
+      tryPlannerLink: "öffne den Planer ohne Konto",
+      tryPlannerSuffix: " →",
+      marketing: {
+        planner: {
+          title: "Routen gemeinsam planen",
+          body: "Skizziere Wander- und Radrouten gemeinsam in Echtzeit. Ohne Konto.",
+        },
+        journal: {
+          title: "Aktivitäten festhalten",
+          body: "Halte deine Touren, Wanderungen und Spaziergänge fest. Privat, mit Freunden geteilt oder öffentlich.",
+        },
+        federation: {
+          title: "Föderiert by design",
+          body: "Deine Journal-Instanz spricht via ActivityPub mit anderen trails.cool-Servern. Folge Freundinnen und Freunden überall.",
+        },
+        ownership: {
+          title: "Deine Daten, immer",
+          body: "Keine Werbung, kein Tracking, kein Datenverkauf. Export als GPX oder JSON jederzeit. MIT-lizenziert und selbst hostbar.",
+        },
+      },
+      feed: {
+        heading: "Aktuelle Aktivitäten",
+        empty: "Noch keine öffentlichen Aktivitäten.",
+      },
+      poweredBy: "Powered by trails.cool — über das Projekt",
+    },
     routes: {
       title: "Routen",
       myRoutes: "Meine Routen",

packages/i18n/src/locales/en.ts

@@ -162,6 +162,36 @@ export default {
     passkeyAdded: "Passkey added! You can now sign in instantly on this device.",
     passkeyStatus: "{{count}} passkey registered",
     passkeyStatus_other: "{{count}} passkeys registered",
+    home: {
+      heroTitle: "Federated outdoor journal",
+      heroSubtitle: "Plan routes, record activities, own your data.",
+      tryPlannerPrefix: "Or ",
+      tryPlannerLink: "try the Planner without an account",
+      tryPlannerSuffix: " →",
+      marketing: {
+        planner: {
+          title: "Plan routes together",
+          body: "Sketch hiking and cycling routes collaboratively in real time. No account needed.",
+        },
+        journal: {
+          title: "Record activities",
+          body: "Log your rides, hikes, and walks. Keep them private, share with friends, or publish to the world.",
+        },
+        federation: {
+          title: "Federated by design",
+          body: "Your Journal instance talks to other trails.cool servers via ActivityPub. Follow friends anywhere.",
+        },
+        ownership: {
+          title: "Your data, always",
+          body: "No ads, no tracking, no data sales. Export everything as GPX or JSON any time. MIT licensed and self-hostable.",
+        },
+      },
+      feed: {
+        heading: "Recent activity",
+        empty: "No public activities yet.",
+      },
+      poweredBy: "Powered by trails.cool — about the project",
+    },
     routes: {
       title: "Routes",
       myRoutes: "My Routes",