check embed.external.uri in backfill

backfill was only checking post text, missing embed-only link cards

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[e-mail]>

src/atproto.zig

···
     uri: []const u8,
     cid: []const u8,
     text: []const u8,
+    embed_uri: ?[]const u8,
 };
 
 /// fetch recent posts from an author's feed.
···
             allocator.free(p.uri);
             allocator.free(p.cid);
             allocator.free(p.text);
+            if (p.embed_uri) |eu| allocator.free(eu);
         }
         posts.deinit(allocator);
     }
···
         const cid_val = post_obj.get("cid") orelse continue;
         if (cid_val != .string) continue;
 
-        // extract record.text
+        // extract record
         const record_val = post_obj.get("record") orelse continue;
         if (record_val != .object) continue;
-        const text_val = record_val.object.get("text") orelse continue;
-        if (text_val != .string) continue;
+
+        // extract text (may be empty)
+        const text_val = record_val.object.get("text");
+        const text = if (text_val) |tv| (if (tv == .string) tv.string else "") else "";
+
+        // extract embed.external.uri if present
+        var embed_uri: ?[]const u8 = null;
+        if (record_val.object.get("embed")) |embed_val| {
+            if (embed_val == .object) {
+                if (embed_val.object.get("external")) |ext_val| {
+                    if (ext_val == .object) {
+                        if (ext_val.object.get("uri")) |eu_val| {
+                            if (eu_val == .string) {
+                                embed_uri = eu_val.string;
+                            }
+                        }
+                    }
+                }
+            }
+        }
 
         try posts.append(allocator, .{
             .uri = try allocator.dupe(u8, uri_val.string),
             .cid = try allocator.dupe(u8, cid_val.string),
-            .text = try allocator.dupe(u8, text_val.string),
+            .text = try allocator.dupe(u8, text),
+            .embed_uri = if (embed_uri) |eu| try allocator.dupe(u8, eu) else null,
         });
     }
 

src/db.zig

···
             alloc.free(p.uri);
             alloc.free(p.cid);
             alloc.free(p.text);
+            if (p.embed_uri) |eu| alloc.free(eu);
         }
         alloc.free(posts);
     }
 
     var added: usize = 0;
     for (posts) |post| {
-        if (filter.textContainsMusicLink(post.text)) {
+        const text_match = filter.textContainsMusicLink(post.text);
+        const embed_match = if (post.embed_uri) |eu| filter.textContainsMusicLink(eu) else false;
+        if (text_match or embed_match) {
             addPost(post.uri, post.cid) catch continue;
             added += 1;
         }