fix: speaker assignment not saving when selected from dropdown

Two issues in the Rust transcript rendering pipeline:

1. Auto-generated channel assignments (from participant list) were appended
   AFTER user assignments, causing HashMap::insert to overwrite user choices
   with auto-generated ones. Fix: reverse ordering so user assignments are
   processed last and take priority.

2. Channel-scoped assignments were gated by complete_channels, which only
   includes RemoteParty for exactly 2-participant meetings. For 3+ participant
   meetings without speaker diarization, user assignments on RemoteParty were
   silently ignored. Fix: remove the complete_channels gate from
   apply_identity_rules and assign_complete_channel_human_id so channel-wide
   assignments are always applied.

Closes #4860

Co-Authored-By: John <john@hyprnote.com>

Author: devin-ai-integration[bot]

crates/transcript/src/render.rs

@@ -71,11 +71,11 @@ pub fn render_transcript_segments(
             .map(|started_at| started_at - base_started_at)
             .unwrap_or(0);
 
-        let (words, mut assignments) =
+        let (words, user_assignments) =
             offset_transcript_data(transcript.words, transcript.assignments, offset);
-        let channel_assignments =
+        let mut assignments =
             channel_assignments_for_participants(&participant_human_ids, self_human_id.as_deref());
-        assignments.extend(channel_assignments);
+        assignments.extend(user_assignments);
 
         let segments = build_segments(&words, &[], &assignments, Some(&segment_options));
         all_segments.extend(segments);
@@ -464,6 +464,40 @@ mod tests {
         assert_eq!(segments[1].text, "remote more");
     }
 
+    #[test]
+    fn user_assignment_overrides_auto_channel_assignment() {
+        let segments = render_transcript_segments(RenderTranscriptRequest {
+            transcripts: vec![RenderTranscriptInput {
+                started_at: Some(0),
+                words: vec![
+                    word("w1", " hello", 0, 100, 0),
+                    word("w2", " remote", 120, 220, 1),
+                ],
+                assignments: vec![channel_assignment("override", ChannelProfile::RemoteParty)],
+            }],
+            participant_human_ids: vec!["self".to_string(), "auto-remote".to_string()],
+            self_human_id: Some("self".to_string()),
+            humans: vec![
+                RenderTranscriptHuman {
+                    human_id: "self".to_string(),
+                    name: "Me".to_string(),
+                },
+                RenderTranscriptHuman {
+                    human_id: "auto-remote".to_string(),
+                    name: "Auto".to_string(),
+                },
+                RenderTranscriptHuman {
+                    human_id: "override".to_string(),
+                    name: "Override".to_string(),
+                },
+            ],
+        });
+
+        assert_eq!(segments.len(), 2);
+        assert_eq!(segments[0].speaker_label, "Me");
+        assert_eq!(segments[1].speaker_label, "Override");
+    }
+
     #[test]
     fn keeps_missing_started_at_rows_anchored_at_zero() {
         let segments = render_transcript_segments(RenderTranscriptRequest {

crates/transcript/src/segments/speakers.rs

@@ -91,9 +91,6 @@ pub(super) fn assign_complete_channel_human_id(segment: &mut ProtoSegment, state
     }
 
     let channel = segment.key.channel;
-    if !state.complete_channels.contains(&channel) {
-        return;
-    }
 
     if let Some(human_id) = state.human_id_by_channel.get(&channel) {
         segment.key = SegmentKey {
@@ -120,7 +117,6 @@ fn apply_identity_rules(
     }
 
     if identity.human_id.is_none()
-        && state.complete_channels.contains(&word.channel)
         && let Some(human_id) = state.human_id_by_channel.get(&word.channel)
     {
         identity.human_id = Some(human_id.clone());

crates/transcript/src/segments/tests.rs

@@ -405,6 +405,16 @@ fn propagates_remote_party_identity_when_channel_marked_complete() {
     assert_eq!(result[0].key.speaker_human_id.as_deref(), Some("remote"));
 }
 
+#[test]
+fn applies_channel_assignment_even_without_complete_channel() {
+    let finals = vec![fw("0", 0, 100, 1), fw("1", 200, 300, 1)];
+    let assignments = vec![channel_human("remote", ChannelProfile::RemoteParty)];
+    // Default options only mark DirectMic as complete, not RemoteParty
+    let result = build_segments(&finals, &[], &assignments, None);
+    assert_eq!(result.len(), 1);
+    assert_eq!(result[0].key.speaker_human_id.as_deref(), Some("remote"));
+}
+
 #[test]
 fn partial_word_ignores_its_own_runtime_hint_and_keeps_previous_segment_key() {
     let finals = vec![fw_si("0", 0, 100, 0, 0)];