fix: use rig prefixes for agent bead IDs

Align rig-scoped agent beads with route prefixes so crew add/prime/status resolve the same IDs across rigs. Add tests that assert rig-prefixed agent IDs in prime and status.

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

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

internal/cmd/prime_test.go

@@ -0,0 +1,97 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/steveyegge/gastown/internal/beads"
+)
+
+func writeTestRoutes(t *testing.T, townRoot string, routes []beads.Route) {
+	t.Helper()
+	beadsDir := filepath.Join(townRoot, ".beads")
+	if err := os.MkdirAll(beadsDir, 0755); err != nil {
+		t.Fatalf("create beads dir: %v", err)
+	}
+	if err := beads.WriteRoutes(beadsDir, routes); err != nil {
+		t.Fatalf("write routes: %v", err)
+	}
+}
+
+func TestGetAgentBeadID_UsesRigPrefix(t *testing.T) {
+	townRoot := t.TempDir()
+	writeTestRoutes(t, townRoot, []beads.Route{
+		{Prefix: "bd-", Path: "beads/mayor/rig"},
+	})
+
+	cases := []struct {
+		name string
+		ctx  RoleContext
+		want string
+	}{
+		{
+			name: "mayor",
+			ctx: RoleContext{
+				Role:     RoleMayor,
+				TownRoot: townRoot,
+			},
+			want: "gt-mayor",
+		},
+		{
+			name: "deacon",
+			ctx: RoleContext{
+				Role:     RoleDeacon,
+				TownRoot: townRoot,
+			},
+			want: "gt-deacon",
+		},
+		{
+			name: "witness",
+			ctx: RoleContext{
+				Role:     RoleWitness,
+				Rig:      "beads",
+				TownRoot: townRoot,
+			},
+			want: "bd-beads-witness",
+		},
+		{
+			name: "refinery",
+			ctx: RoleContext{
+				Role:     RoleRefinery,
+				Rig:      "beads",
+				TownRoot: townRoot,
+			},
+			want: "bd-beads-refinery",
+		},
+		{
+			name: "polecat",
+			ctx: RoleContext{
+				Role:     RolePolecat,
+				Rig:      "beads",
+				Polecat:  "lex",
+				TownRoot: townRoot,
+			},
+			want: "bd-beads-polecat-lex",
+		},
+		{
+			name: "crew",
+			ctx: RoleContext{
+				Role:     RoleCrew,
+				Rig:      "beads",
+				Polecat:  "lex",
+				TownRoot: townRoot,
+			},
+			want: "bd-beads-crew-lex",
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := getAgentBeadID(tc.ctx)
+			if got != tc.want {
+				t.Fatalf("getAgentBeadID() = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}