Reactions and votes stop failing silently

`reactToStory` ran its work inside `runCatching` and threw the result
away. A reaction that never reached the relay looked exactly like one that
did: the strip redrew, nothing said otherwise, and the emoji was simply
not there afterwards. That is "I react to a story and the reaction doesn't
take", reported and until now unexplained.

`reactToMessage` and `votePoll` do the same thing, so they get the same
treatment. `replyToStory`, sitting immediately below the story reaction,
has always handled its failure properly; these three were the ones that
did not.

There are more of these in this file. They are not all bugs, plenty are
genuinely fire-and-forget, and a heuristic sweep gets it wrong in both
directions: mine first reported `addBuddy` as unhandled when its handler
is fifteen lines down, then missed `reactToStory` because it saw the
neighbouring reply's handler. These three were read rather than matched.

1474 unit tests green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/src/main/kotlin/io/flamenet/messenger/app/MessengerViewModel.kt

@@ -1219,6 +1219,9 @@ class MessengerViewModel(
         val current = session ?: return@launch
         withContext(Dispatchers.IO) {
             runCatching { current.conversations.vote(pollId, current.userId, choice) }
+        }.onFailure { failure ->
+            // A vote that did not land must not look like one that did.
+            update { it.copy(error = describe(failure)) }
         }
         refreshPolls()
     }
@@ -3215,6 +3218,9 @@ class MessengerViewModel(
                     privateToAuthor = privately,
                 )
             }
+        }.onFailure { failure ->
+            // Same as the story reaction: a tap that silently did nothing.
+            update { it.copy(error = describe(failure)) }
         }
         update {
             it.copy(
@@ -3335,8 +3341,16 @@ class MessengerViewModel(
         story: Vault.Story,
     ) = viewModelScope.launch {
         val current = session ?: return@launch
-        withContext(Dispatchers.IO) { runCatching { current.reactToStory(emoji, story) } }
+        // The outcome is looked at. This threw the failure away, so a reaction
+        // that did not reach the relay looked exactly like one that did: the
+        // strip redrew and nothing said otherwise. "The reaction doesn't take"
+        // is what that is from the outside.
+        val done =
+            withContext(Dispatchers.IO) { runCatching { current.reactToStory(emoji, story) } }
         update { it.copy(stories = current.stories()) }
+        done.onFailure { failure ->
+            update { it.copy(error = describe(failure)) }
+        }
     }
 
     /** Reply privately to somebody's story, in the ordinary conversation. */