Merge branch 'claude/nostalgic-wright-acfc25': inline offer photos

Market offers carry a small base64 data-URI thumbnail embedded in the Nostr
event (no media server); full photo stays in the encrypted inventory. Blossom
alternative parked on branch parked/offer-photos-blossom.

# Conflicts:
#	apps/app_seeds/lib/i18n/strings.g.dart

apps/app_seeds/lib/services/offer_thumbnail.dart

@@ -0,0 +1,56 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:image/image.dart' as img;
+
+/// Builds a tiny `data:image/jpeg;base64,…` thumbnail from a full photo, small
+/// enough to ride *inside* a Nostr offer event — no media server, fully
+/// decentralized. The full-resolution photo stays in the encrypted local
+/// inventory; only this shrunken preview is published so peers can see the seed.
+///
+/// Relays cap event size, so we downscale (longest edge) and re-encode until the
+/// base64 fits under [maxBytes]. Returns null when the bytes aren't a decodable
+/// image or no size small enough is reachable — the offer then publishes without
+/// a photo (graceful, never a hard failure).
+String? offerThumbnailDataUri(
+  Uint8List bytes, {
+  int maxBytes = 40000,
+  List<int> edges = const [320, 256, 192, 128],
+  int quality = 68,
+}) {
+  try {
+    final decoded = img.decodeImage(bytes);
+    if (decoded == null) return null;
+
+    for (final edge in edges) {
+      final resized = _fitWithin(decoded, edge);
+      final jpeg = img.encodeJpg(resized, quality: quality);
+      final b64 = base64.encode(jpeg);
+      if (b64.length <= maxBytes) return 'data:image/jpeg;base64,$b64';
+    }
+    return null; // even the smallest edge didn't fit — skip the image
+  } catch (_) {
+    return null; // undecodable/corrupt bytes — publish without a photo
+  }
+}
+
+/// Extracts the raw bytes from a `data:...;base64,…` URI, or null when [uri] is
+/// not a base64 data URI. Used by the UI to render an inline thumbnail with
+/// `Image.memory` instead of a network fetch.
+Uint8List? decodeDataUri(String uri) {
+  if (!uri.startsWith('data:')) return null;
+  try {
+    return Uri.parse(uri).data?.contentAsBytes();
+  } on FormatException {
+    return null;
+  }
+}
+
+/// Resizes [image] so its longest edge is at most [edge], preserving aspect
+/// ratio. Never upscales a photo that's already smaller.
+img.Image _fitWithin(img.Image image, int edge) {
+  if (image.width <= edge && image.height <= edge) return image;
+  return image.width >= image.height
+      ? img.copyResize(image, width: edge)
+      : img.copyResize(image, height: edge);
+}