feat: Wire MQ lifecycle events to gt feed display (gt-lak31)

- Add MQ event types and logging in mrqueue/events.go
- Have refinery emit merge_started, merged, merge_failed, merge_skipped events
- Create MQEventSource to read from mq_events.jsonl
- Add MultiSource to combine events from bd activity and MQ events
- Add color coding: green for merged, red for failed
- Update feed help with MQ event symbols

Events are stored in .beads/mq_events.jsonl and displayed in the feed TUI
with appropriate symbols and colors.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/tui/feed/mq_source_test.go

@@ -0,0 +1,144 @@
+package feed
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/steveyegge/gastown/internal/mrqueue"
+)
+
+func TestParseMQEventLine(t *testing.T) {
+	tests := []struct {
+		name         string
+		event        mrqueue.Event
+		wantType     string
+		wantTarget   string
+		wantContains string // Substring in message
+	}{
+		{
+			name: "merge_started",
+			event: mrqueue.Event{
+				Timestamp: time.Now(),
+				Type:      mrqueue.EventMergeStarted,
+				MRID:      "mr-123",
+				Branch:    "polecat/nux",
+				Target:    "main",
+				Worker:    "nux",
+				Rig:       "gastown",
+			},
+			wantType:     "merge_started",
+			wantTarget:   "mr-123",
+			wantContains: "Merge started",
+		},
+		{
+			name: "merged",
+			event: mrqueue.Event{
+				Timestamp:   time.Now(),
+				Type:        mrqueue.EventMerged,
+				MRID:        "mr-456",
+				Branch:      "polecat/toast",
+				Target:      "main",
+				Worker:      "toast",
+				Rig:         "gastown",
+				MergeCommit: "abc123def456789",
+			},
+			wantType:     "merged",
+			wantTarget:   "mr-456",
+			wantContains: "abc123de", // Short SHA
+		},
+		{
+			name: "merge_failed",
+			event: mrqueue.Event{
+				Timestamp: time.Now(),
+				Type:      mrqueue.EventMergeFailed,
+				MRID:      "mr-789",
+				Branch:    "polecat/capable",
+				Target:    "main",
+				Worker:    "capable",
+				Rig:       "gastown",
+				Reason:    "conflict in main.go",
+			},
+			wantType:     "merge_failed",
+			wantTarget:   "mr-789",
+			wantContains: "conflict in main.go",
+		},
+		{
+			name: "merge_skipped",
+			event: mrqueue.Event{
+				Timestamp: time.Now(),
+				Type:      mrqueue.EventMergeSkipped,
+				MRID:      "mr-999",
+				Branch:    "polecat/skip",
+				Target:    "main",
+				Reason:    "already merged",
+			},
+			wantType:     "merge_skipped",
+			wantTarget:   "mr-999",
+			wantContains: "already merged",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Marshal to JSON line
+			data, err := json.Marshal(tt.event)
+			if err != nil {
+				t.Fatalf("Failed to marshal event: %v", err)
+			}
+
+			// Parse the line
+			result := parseMQEventLine(string(data))
+			if result == nil {
+				t.Fatal("parseMQEventLine returned nil")
+			}
+
+			if result.Type != tt.wantType {
+				t.Errorf("Type = %q, want %q", result.Type, tt.wantType)
+			}
+
+			if result.Target != tt.wantTarget {
+				t.Errorf("Target = %q, want %q", result.Target, tt.wantTarget)
+			}
+
+			if tt.wantContains != "" && !contains(result.Message, tt.wantContains) {
+				t.Errorf("Message = %q, want to contain %q", result.Message, tt.wantContains)
+			}
+
+			// Actor should be refinery
+			if result.Actor != "refinery" {
+				t.Errorf("Actor = %q, want %q", result.Actor, "refinery")
+			}
+
+			if result.Role != "refinery" {
+				t.Errorf("Role = %q, want %q", result.Role, "refinery")
+			}
+		})
+	}
+}
+
+func TestParseMQEventLineEmpty(t *testing.T) {
+	result := parseMQEventLine("")
+	if result != nil {
+		t.Error("Expected nil for empty line")
+	}
+
+	result = parseMQEventLine("   ")
+	if result != nil {
+		t.Error("Expected nil for whitespace-only line")
+	}
+
+	result = parseMQEventLine("not valid json")
+	if result != nil {
+		t.Error("Expected nil for invalid JSON")
+	}
+}
+
+func contains(s, substr string) bool {
+	for i := 0; i <= len(s)-len(substr); i++ {
+		if s[i:i+len(substr)] == substr {
+			return true
+		}
+	}
+	return false
+}