Show similar earlier incidents and let notes be marked as the fix

The incident view gets a "Seen before" section from the server's new
/similar endpoint; an older server without it just shows nothing. C adds a
note as the resolution note, alongside c for a plain note. Needs the
server release that adds /similar.

Claude-Session: https://claude.ai/code/session_01MMados3BD1oSjevHxbmVqU

internal/tui/update.go

@@ -145,6 +145,7 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case incidentDetailFetchedMsg:
 		m.selectedIncident = msg.incident
 		m.timeline = msg.timeline
+		m.similar = msg.similar
 		m.detailLoading = false
 		if m.noteCursor >= len(noteEvents(m.timeline)) {
 			m.noteCursor = -1
@@ -938,8 +939,9 @@ func (m Model) handleIncidentDetailKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 		m.mode = modeDashboard
 		return m, archiveIncidentCmd(m.client, inc.ID, m.activeTeamID, m.incidentFilter)
 
-	case "c":
+	case "c", "C":
 		m.mode = modeNote
+		m.notePinned = msg.String() == "C"
 		m.noteInput.Reset()
 		m.noteInput.Focus()
 		m.detailViewport.Height = m.detailViewportHeight()
@@ -1032,7 +1034,7 @@ func (m Model) handleNoteKey(msg tea.KeyMsg) (Model, tea.Cmd) {
 		m.mode = modeIncidentDetail
 		m.noteInput.Blur()
 		m.detailViewport.Height = m.detailViewportHeight()
-		return m, addNoteCmd(m.client, m.selectedIncident.ID, content)
+		return m, addNoteCmd(m.client, m.selectedIncident.ID, content, m.notePinned)
 	}
 
 	return m, nil