Remove obsolete renumber and stale commands, fix test

- Remove renumber.go: Hash IDs eliminated need for ID compaction
- Remove stale.go: Executor/heartbeat tables were never implemented
- Fix TestListCommand: duplicate dependency constraint violation
- Update comments removing references to removed commands

Amp-Thread-ID: https://ampcode.com/threads/T-3dcd8681-c7d3-4fe1-9750-b38279b56cdb
Co-authored-by: Amp <amp@ampcode.com>

cmd/bd/stale_test.go

@@ -1,82 +0,0 @@
-package main
-
-import (
-	"testing"
-	"time"
-)
-
-func TestFormatDuration(t *testing.T) {
-	tests := []struct {
-		name     string
-		duration time.Duration
-		want     string
-	}{
-		{
-			name:     "less than a minute",
-			duration: 45 * time.Second,
-			want:     "45 seconds",
-		},
-		{
-			name:     "exactly one minute",
-			duration: 60 * time.Second,
-			want:     "1 minutes",
-		},
-		{
-			name:     "several minutes",
-			duration: 5 * time.Minute,
-			want:     "5 minutes",
-		},
-		{
-			name:     "one hour",
-			duration: 60 * time.Minute,
-			want:     "1.0 hours",
-		},
-		{
-			name:     "several hours",
-			duration: 3*time.Hour + 30*time.Minute,
-			want:     "3.5 hours",
-		},
-		{
-			name:     "one day",
-			duration: 24 * time.Hour,
-			want:     "1.0 days",
-		},
-		{
-			name:     "multiple days",
-			duration: 3*24*time.Hour + 12*time.Hour,
-			want:     "3.5 days",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got := formatDuration(tt.duration)
-			if got != tt.want {
-				t.Errorf("formatDuration(%v) = %q, want %q", tt.duration, got, tt.want)
-			}
-		})
-	}
-}
-
-func TestStaleIssueInfo(t *testing.T) {
-	// Test that StaleIssueInfo struct can be created and serialized
-	info := &StaleIssueInfo{
-		IssueID:            "bd-42",
-		IssueTitle:         "Test Issue",
-		IssuePriority:      1,
-		ExecutorInstanceID: "exec-123",
-		ExecutorStatus:     "stopped",
-		ExecutorHostname:   "localhost",
-		ExecutorPID:        12345,
-		LastHeartbeat:      time.Now().Add(-10 * time.Minute),
-		ClaimedAt:          time.Now().Add(-30 * time.Minute),
-		ClaimedDuration:    "30 minutes",
-	}
-
-	if info.IssueID != "bd-42" {
-		t.Errorf("Expected IssueID bd-42, got %s", info.IssueID)
-	}
-	if info.ExecutorStatus != "stopped" {
-		t.Errorf("Expected ExecutorStatus stopped, got %s", info.ExecutorStatus)
-	}
-}