feat: integrate migration detection into bd doctor (bd-7l27)

Add a consolidated "Pending Migrations" check to bd doctor that:
- Detects sequential ID usage (suggests bd migrate hash-ids)
- Detects legacy deletions.jsonl (suggests bd migrate tombstones)
- Detects missing sync-branch config (suggests bd migrate sync)
- Detects database version mismatches (suggests bd migrate)

Also updates existing checks to use correct modern commands:
- CheckIDFormat: bd migrate hash-ids (was bd migrate --to-hash-ids)
- CheckDeletionsManifest: bd migrate tombstones (was bd migrate-tombstones)
- CheckSyncBranchConfig: bd migrate sync beads-sync (was config.yaml edit)

Removes TODO(bd-7l27) comments from migrate_*.go files.

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

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

cmd/bd/doctor/migration_test.go

@@ -0,0 +1,188 @@
+package doctor
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCheckPendingMigrations(t *testing.T) {
+	tests := []struct {
+		name           string
+		setup          func(t *testing.T, dir string)
+		wantStatus     string
+		wantMessage    string
+		wantMigrations int
+	}{
+		{
+			name:        "no beads directory",
+			setup:       func(t *testing.T, dir string) {},
+			wantStatus:  StatusOK,
+			wantMessage: "None required",
+		},
+		{
+			name: "empty beads directory",
+			setup: func(t *testing.T, dir string) {
+				if err := os.MkdirAll(filepath.Join(dir, ".beads"), 0755); err != nil {
+					t.Fatalf("failed to create .beads: %v", err)
+				}
+			},
+			wantStatus:  StatusOK,
+			wantMessage: "None required",
+		},
+		{
+			name: "deletions.jsonl exists with entries",
+			setup: func(t *testing.T, dir string) {
+				beadsDir := filepath.Join(dir, ".beads")
+				if err := os.MkdirAll(beadsDir, 0755); err != nil {
+					t.Fatalf("failed to create .beads: %v", err)
+				}
+				// Create deletions.jsonl with an entry
+				content := `{"id":"bd-test","ts":"2024-01-01T00:00:00Z","by":"test"}`
+				if err := os.WriteFile(filepath.Join(beadsDir, "deletions.jsonl"), []byte(content), 0644); err != nil {
+					t.Fatalf("failed to create deletions.jsonl: %v", err)
+				}
+			},
+			wantStatus:     StatusWarning,
+			wantMigrations: 1,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+			if err != nil {
+				t.Fatalf("failed to create temp dir: %v", err)
+			}
+			defer os.RemoveAll(tmpDir)
+
+			tt.setup(t, tmpDir)
+
+			check := CheckPendingMigrations(tmpDir)
+
+			if check.Status != tt.wantStatus {
+				t.Errorf("status = %q, want %q", check.Status, tt.wantStatus)
+			}
+
+			if tt.wantMessage != "" && check.Message != tt.wantMessage {
+				t.Errorf("message = %q, want %q", check.Message, tt.wantMessage)
+			}
+
+			if check.Category != CategoryMaintenance {
+				t.Errorf("category = %q, want %q", check.Category, CategoryMaintenance)
+			}
+		})
+	}
+}
+
+func TestDetectPendingMigrations(t *testing.T) {
+	t.Run("no beads directory returns empty", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		migrations := DetectPendingMigrations(tmpDir)
+		if len(migrations) != 0 {
+			t.Errorf("expected 0 migrations, got %d", len(migrations))
+		}
+	})
+
+	t.Run("empty beads directory returns empty", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		if err := os.MkdirAll(filepath.Join(tmpDir, ".beads"), 0755); err != nil {
+			t.Fatalf("failed to create .beads: %v", err)
+		}
+
+		migrations := DetectPendingMigrations(tmpDir)
+		if len(migrations) != 0 {
+			t.Errorf("expected 0 migrations, got %d", len(migrations))
+		}
+	})
+
+	t.Run("deletions.jsonl triggers tombstones migration", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		beadsDir := filepath.Join(tmpDir, ".beads")
+		if err := os.MkdirAll(beadsDir, 0755); err != nil {
+			t.Fatalf("failed to create .beads: %v", err)
+		}
+
+		// Create deletions.jsonl with an entry
+		content := `{"id":"bd-test","ts":"2024-01-01T00:00:00Z","by":"test"}`
+		if err := os.WriteFile(filepath.Join(beadsDir, "deletions.jsonl"), []byte(content), 0644); err != nil {
+			t.Fatalf("failed to create deletions.jsonl: %v", err)
+		}
+
+		migrations := DetectPendingMigrations(tmpDir)
+		if len(migrations) != 1 {
+			t.Errorf("expected 1 migration, got %d", len(migrations))
+			return
+		}
+
+		if migrations[0].Name != "tombstones" {
+			t.Errorf("migration name = %q, want %q", migrations[0].Name, "tombstones")
+		}
+
+		if migrations[0].Command != "bd migrate tombstones" {
+			t.Errorf("migration command = %q, want %q", migrations[0].Command, "bd migrate tombstones")
+		}
+	})
+}
+
+func TestNeedsTombstonesMigration(t *testing.T) {
+	t.Run("no deletions.jsonl returns false", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		if needsTombstonesMigration(tmpDir) {
+			t.Error("expected false for non-existent deletions.jsonl")
+		}
+	})
+
+	t.Run("empty deletions.jsonl returns false", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		if err := os.WriteFile(filepath.Join(tmpDir, "deletions.jsonl"), []byte(""), 0644); err != nil {
+			t.Fatalf("failed to create deletions.jsonl: %v", err)
+		}
+
+		if needsTombstonesMigration(tmpDir) {
+			t.Error("expected false for empty deletions.jsonl")
+		}
+	})
+
+	t.Run("deletions.jsonl with entries returns true", func(t *testing.T) {
+		tmpDir, err := os.MkdirTemp("", "bd-doctor-migration-*")
+		if err != nil {
+			t.Fatalf("failed to create temp dir: %v", err)
+		}
+		defer os.RemoveAll(tmpDir)
+
+		content := `{"id":"bd-test","ts":"2024-01-01T00:00:00Z","by":"test"}`
+		if err := os.WriteFile(filepath.Join(tmpDir, "deletions.jsonl"), []byte(content), 0644); err != nil {
+			t.Fatalf("failed to create deletions.jsonl: %v", err)
+		}
+
+		if !needsTombstonesMigration(tmpDir) {
+			t.Error("expected true for deletions.jsonl with entries")
+		}
+	})
+}