feat(market): fix publish-duplicates, add offer detail page + filters

The vecino/market view had three gaps:

- Publishing inventory duplicated the listing. discover() appended every
  offer the relay streamed, but relays legitimately resend an addressable
  NIP-99 event (stored copy + live echo on publish). Merge by
  (authorPubkeyHex, id) so each offer appears once; two authors reusing a
  lot id stay distinct.
- No product detail. Tapping a card jumped straight to chat. Add a
  read-only "product page" (MarketOfferDetailScreen) with title, mode,
  category, eco badge, coarse location, price, a "Shared by" seller
  section (profile fetched by pubkey) and the message button. Reached via
  a new /market/offer route; cards are now fully tappable. Shows only what
  the network already carries — no photos/description added to the wire.
- No filters. Add a filter bar (type, category, eco) mirroring inventory,
  each chip group shown only when a discovered offer can match it. To make
  the eco filter real, publish the organic flag on the wire: Offer.isOrganic
  -> NIP-99 'organic' tag -> OfferMapper -> ShareableLot.

Tests: commons_core organic round-trip; app-side dedup, two-author
separation, filter logic, mapper passthrough; detail-screen widget tests.
i18n keys added to en/es/pt/ast and slang regenerated.

apps/app_seeds/lib/app.dart

@@ -1,3 +1,4 @@
+import 'package:commons_core/commons_core.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -25,6 +26,7 @@ import 'ui/chat_screen.dart';
 import 'ui/home_screen.dart';
 import 'ui/intro_screen.dart';
 import 'ui/inventory_list_screen.dart';
+import 'ui/market_offer_detail_screen.dart';
 import 'ui/market_screen.dart';
 import 'ui/offline_banner.dart';
 import 'ui/profile_screen.dart';
@@ -123,6 +125,20 @@ class TaneApp extends StatelessWidget {
               outbox: outbox,
             ),
           ),
+        if (social != null && socialSettings != null)
+          GoRoute(
+            path: '/market/offer',
+            builder: (context, state) {
+              final offer = state.extra as Offer;
+              return MarketOfferDetailScreen(
+                offer: offer,
+                social: social,
+                settings: socialSettings,
+                mine: offer.authorPubkeyHex == social.publicKeyHex,
+                profileCache: profileCache,
+              );
+            },
+          ),
         if (social != null && socialSettings != null && messageStore != null)
           GoRoute(
             path: '/messages',