Fix bd-in7q: prevent migrate-tombstones from corrupting deletions manifest (#554)

Root cause: bd doctor hydrate was re-adding migrated tombstones to the
deletions manifest because getCurrentJSONLIDs() included all issues,
including tombstones. When compared against git history, tombstones
appeared as 'deleted' and were incorrectly added to the manifest as new
deletions, corrupting the database on next sync.

Fix: Skip tombstone-status issues in getCurrentJSONLIDs() so they don't
participate in deletion detection. Tombstones represent already-recorded
deletions/migrations and shouldn't be treated as active issues.

Changes:
- cmd/bd/doctor/fix/deletions.go: Skip tombstones in getCurrentJSONLIDs()
- cmd/bd/doctor/fix/deletions_test.go: New tests for tombstone skipping
- cmd/bd/migrate_tombstones_test.go: Test that tombstones are valid

This fixes the bug where 'bd migrate-tombstones' followed by 'bd sync'
would add thousands of deletion records with author 'bd-doctor-hydrate'

cmd/bd/migrate_tombstones_test.go

@@ -224,3 +224,69 @@ func TestConvertDeletionRecordToTombstone(t *testing.T) {
 		t.Errorf("Expected empty OriginalType, got %s", tombstone.OriginalType)
 	}
 }
+
+// TestMigrateTombstones_TombstonesAreValid verifies that migrated tombstones
+// have the tombstone status set, so they won't be re-added to deletions manifest (bd-in7q fix)
+func TestMigrateTombstones_TombstonesAreValid(t *testing.T) {
+	// Setup: create temp .beads directory
+	tmpDir := t.TempDir()
+	beadsDir := filepath.Join(tmpDir, ".beads")
+	if err := os.MkdirAll(beadsDir, 0755); err != nil {
+		t.Fatalf("Failed to create .beads dir: %v", err)
+	}
+
+	// Create deletions.jsonl with some entries
+	deletionsPath := deletions.DefaultPath(beadsDir)
+	deleteTime := time.Now().Add(-24 * time.Hour)
+
+	records := []deletions.DeletionRecord{
+		{ID: "test-abc", Timestamp: deleteTime, Actor: "alice", Reason: "duplicate"},
+	}
+
+	for _, record := range records {
+		if err := deletions.AppendDeletion(deletionsPath, record); err != nil {
+			t.Fatalf("Failed to write deletion: %v", err)
+		}
+	}
+
+	// Create empty issues.jsonl
+	issuesPath := filepath.Join(beadsDir, "issues.jsonl")
+	if err := os.WriteFile(issuesPath, []byte{}, 0600); err != nil {
+		t.Fatalf("Failed to create issues.jsonl: %v", err)
+	}
+
+	// Load deletions
+	loadResult, err := deletions.LoadDeletions(deletionsPath)
+	if err != nil {
+		t.Fatalf("LoadDeletions failed: %v", err)
+	}
+
+	// Convert to tombstones (simulating what migrate-tombstones does)
+	var tombstones []*types.Issue
+	for _, record := range loadResult.Records {
+		ts := convertDeletionRecordToTombstone(record)
+		// CRITICAL: Tombstones must have status "tombstone"
+		// so they won't be re-added to deletions manifest on next sync (bd-in7q)
+		if ts.Status != types.StatusTombstone {
+			t.Errorf("Converted tombstone must have status 'tombstone', got %s", ts.Status)
+		}
+		tombstones = append(tombstones, ts)
+	}
+
+	// Verify tombstone is valid
+	if len(tombstones) != 1 {
+		t.Fatalf("Expected 1 tombstone, got %d", len(tombstones))
+	}
+	ts := tombstones[0]
+
+	// These fields are critical for the doctor fix to work correctly
+	if ts.ID != "test-abc" {
+		t.Errorf("Expected ID test-abc, got %s", ts.ID)
+	}
+	if ts.Status != types.StatusTombstone {
+		t.Errorf("Expected status tombstone, got %s", ts.Status)
+	}
+	if ts.DeletedBy != "alice" {
+		t.Errorf("Expected DeletedBy 'alice', got %s", ts.DeletedBy)
+	}
+}