refactor(trust): ego-centric trust replaces the global Duniter membership

The global membership rule (curated bootstrap referents + sigQty/stepMax
parameters) solved sybil-proof identity for a UBI — a problem this app
doesn't have — and its screen leaked graph jargon (npub roots, parameter
steppers). Trust is now computed from the user's own position only:
you vouch / vouched by people you know (distance <=2) / vouched by N.

- TrustCubit: drop networkMember tier, referents and params; keep the
  circle rule and the 365-day vouch expiry (renewable, self-pruning).
- Delete TrustReferents, WotSettings, TrustNetworkScreen and the bundled
  referents asset; unwire injector/bootstrap/app/chat.
- New 'Your people' screen (/your-people, from the profile): who you
  vouch for (revocable) and who vouches for you, names via ProfileCache.
- i18n: wot.* removed, yourPeople.* added (en/es/pt/ast); trust.member
  removed. Kind 30777 events on relays stay fully compatible — only the
  interpretation changes.

apps/app_seeds/pubspec.yaml

@@ -130,9 +130,6 @@ flutter:
   # Seed strings for slang live under lib/i18n (not a Flutter asset; compiled).
   assets:
     - assets/catalog/species.json
-    # Web-of-trust bootstrap referents (Duniter "seeds"). Empty until real
-    # founding identities are curated; users bootstrap by adding their own.
-    - assets/trust/referents.json
     - assets/logo.png
     # Bundled so the Linux runner can use it as the GTK window icon.
     - assets/icon.png