feat: consolidate maintenance commands into bd doctor --fix (bd-bqcc)

Add new Maintenance category to bd doctor with checks for:
- Stale closed issues (older than 30 days)
- Expired tombstones (older than TTL)
- Compaction candidates (info only)

Add fix handlers for cleanup and tombstone pruning via bd doctor --fix.
Add deprecation hints to cleanup, compact, and detect-pollution commands
suggesting users try bd doctor instead.

This consolidation reduces cognitive load - users just need to remember
'bd doctor' for health checks and 'bd doctor --fix' for maintenance.

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

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

cmd/bd/doctor/fix/maintenance_test.go

@@ -0,0 +1,77 @@
+package fix
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestStaleClosedIssues_NoDatabase(t *testing.T) {
+	// Create temp directory with .beads but no database
+	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)
+	}
+
+	// Should succeed without database
+	err := StaleClosedIssues(tmpDir)
+	if err != nil {
+		t.Errorf("expected no error, got: %v", err)
+	}
+}
+
+func TestStaleClosedIssues_NoBeadsDir(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	// Should fail without .beads directory
+	err := StaleClosedIssues(tmpDir)
+	if err == nil {
+		t.Error("expected error for missing .beads directory")
+	}
+}
+
+func TestExpiredTombstones_NoJSONL(t *testing.T) {
+	// Create temp directory with .beads but no JSONL
+	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)
+	}
+
+	// Should succeed without JSONL
+	err := ExpiredTombstones(tmpDir)
+	if err != nil {
+		t.Errorf("expected no error, got: %v", err)
+	}
+}
+
+func TestExpiredTombstones_NoBeadsDir(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	// Should fail without .beads directory
+	err := ExpiredTombstones(tmpDir)
+	if err == nil {
+		t.Error("expected error for missing .beads directory")
+	}
+}
+
+func TestExpiredTombstones_EmptyJSONL(t *testing.T) {
+	// Create temp directory with .beads and empty JSONL
+	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)
+	}
+
+	jsonlPath := filepath.Join(beadsDir, "issues.jsonl")
+	if err := os.WriteFile(jsonlPath, []byte{}, 0644); err != nil {
+		t.Fatalf("failed to create issues.jsonl: %v", err)
+	}
+
+	// Should succeed with empty JSONL
+	err := ExpiredTombstones(tmpDir)
+	if err != nil {
+		t.Errorf("expected no error, got: %v", err)
+	}
+}