Badges, video stories, and parental controls

Launcher badges on the message notification (the service notice
explicitly never badges). Stories accept picked videos — validated
against a 30s/9MB cap rather than transcoded, said honestly when
refused — and play looping in the card via the framework player. The
wire's dur field travels for any attachment that has one.

Parental controls mirror iOS: a parent's PIN guards adding contacts,
stories, and calls; incoming calls answer busy; sign-up gains an
on-device age gate that stores nothing. The server learns nothing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/src/main/kotlin/io/flamenet/client/Conversations.kt

@@ -225,12 +225,14 @@ class Conversations(
         caption: String?,
         toUserIds: List<Long>,
         lifetimeSeconds: Double = STORY_LIFETIME_SECONDS,
+        duration: Double = 0.0,
     ): StoryPosted {
         val sealed = Attachment.seal(data)
         val id = relay.uploadAttachment(sealed.blob)
         val ref = Attachment.Ref(
             kind = Attachment.STORY, id = id, key = sealed.key, digest = sealed.digest,
             bytes = sealed.blob.size, mime = mime, width = width, height = height,
+            duration = duration,
             expires = System.currentTimeMillis() / 1000.0 + lifetimeSeconds,
         )
         val body = Content.attachment(ref, caption, null)