feat(trust): full Duniter web-of-trust membership (params + referents)

Slice 4 of Block 2. The pure rule was already parameterised; this adds the
policy, cold-start and UI around it.

- commons_core: WotParams (sigQty/stepMax/sigValidity, Duniter defaults) +
  WebOfTrust.membersWith; npubToHex helper (NIP-19 decode) for adding roots.
- WotSettings (keystore): the active parameters, configurable — a young
  network loosens them and tightens as it grows, as Ğ1 did. Defaults Duniter.
- TrustReferents: the bootstrap 'seeds' membership is measured from — a
  bundled asset (empty until real founders are curated, no invented keys)
  unioned with referents the user adds by npub/QR. Honest cold-start.
- TrustCubit: computes the full membership verdict against referents+params
  alongside the personal circle, and exposes a TrustTier (networkMember >
  inYourCircle > vouched > unknown). Certifications issued with the active
  validity (they expire and renew, Duniter rule).
- UI: chat trust badge by tier; a 'Network of trust' screen (manage roots +
  advanced params) reached from the profile. i18n en/es/pt/ast.

Tests: WotParams/membersWith, npubToHex, TrustReferents, WotSettings, and
TrustCubit tiers/membership. Resolves the WoT-parameters decision
(open-decisions §B). Trust net stays empty/undetermined until seeded — by
design; users bootstrap their own roots.

apps/app_seeds/lib/i18n/es.i18n.json

@@ -445,6 +445,28 @@
     "count": "Avalada por {n}",
     "vouch": "Conozco a esta persona",
     "vouched": "Avalas a esta persona",
-    "circle": "En tu círculo"
+    "circle": "En tu círculo",
+    "member": "Miembro de confianza de la red"
+  },
+  "wot": {
+    "title": "Red de confianza",
+    "open": "Red de confianza",
+    "help": "Cómo se decide quién es miembro de confianza: la gente se avala entre sí, y la confianza se extiende desde un conjunto de raíces fundadoras.",
+    "roots": "Raíces de confianza",
+    "rootsHelp": "Las identidades fundadoras que anclan la red. Añade a quien te fíes (pega su código de identidad); la membresía se mide hacia fuera desde ellas.",
+    "noRoots": "Aún no hay raíces de confianza — no se puede calcular la membresía hasta sembrar la red.",
+    "addRoot": "Añadir una raíz de confianza",
+    "rootHint": "Pega un código de identidad (npub…)",
+    "add": "Añadir",
+    "rootAdded": "Raíz de confianza añadida",
+    "rootInvalid": "Ese no es un código de identidad válido",
+    "remove": "Quitar",
+    "params": "Parámetros avanzados",
+    "paramsHelp": "Reglas Duniter. Aflójalas para una red joven; apriétalas según crece.",
+    "sigQty": "Avales para ser miembro",
+    "stepMax": "Distancia máxima a una raíz",
+    "validityDays": "Validez del aval (días)",
+    "reset": "Restablecer a valores Duniter",
+    "saved": "Guardado"
   }
 }