feat(security): add GIT_AUTHOR_EMAIL per agent type

Phase 1 of agent security model: Set distinct email addresses for each
agent type to improve audit trail clarity.

Email format:
- Town-level: {role}@gastown.local (mayor, deacon, boot)
- Rig-level: {rig}-{role}@gastown.local (witness, refinery)
- Named agents: {rig}-{role}-{name}@gastown.local (polecat, crew)

This makes git log filtering by agent type trivial and provides a
foundation for per-agent key separation in future phases.

Refs: hq-biot

internal/config/env.go

@@ -49,36 +49,43 @@ func AgentEnv(cfg AgentEnvConfig) map[string]string {
 	case "mayor":
 		env["BD_ACTOR"] = "mayor"
 		env["GIT_AUTHOR_NAME"] = "mayor"
+		env["GIT_AUTHOR_EMAIL"] = "mayor@gastown.local"
 
 	case "deacon":
 		env["BD_ACTOR"] = "deacon"
 		env["GIT_AUTHOR_NAME"] = "deacon"
+		env["GIT_AUTHOR_EMAIL"] = "deacon@gastown.local"
 
 	case "boot":
 		env["BD_ACTOR"] = "deacon-boot"
 		env["GIT_AUTHOR_NAME"] = "boot"
+		env["GIT_AUTHOR_EMAIL"] = "boot@gastown.local"
 
 	case "witness":
 		env["GT_RIG"] = cfg.Rig
 		env["BD_ACTOR"] = fmt.Sprintf("%s/witness", cfg.Rig)
 		env["GIT_AUTHOR_NAME"] = fmt.Sprintf("%s/witness", cfg.Rig)
+		env["GIT_AUTHOR_EMAIL"] = fmt.Sprintf("%s-witness@gastown.local", cfg.Rig)
 
 	case "refinery":
 		env["GT_RIG"] = cfg.Rig
 		env["BD_ACTOR"] = fmt.Sprintf("%s/refinery", cfg.Rig)
 		env["GIT_AUTHOR_NAME"] = fmt.Sprintf("%s/refinery", cfg.Rig)
+		env["GIT_AUTHOR_EMAIL"] = fmt.Sprintf("%s-refinery@gastown.local", cfg.Rig)
 
 	case "polecat":
 		env["GT_RIG"] = cfg.Rig
 		env["GT_POLECAT"] = cfg.AgentName
 		env["BD_ACTOR"] = fmt.Sprintf("%s/polecats/%s", cfg.Rig, cfg.AgentName)
 		env["GIT_AUTHOR_NAME"] = cfg.AgentName
+		env["GIT_AUTHOR_EMAIL"] = fmt.Sprintf("%s-polecat-%s@gastown.local", cfg.Rig, cfg.AgentName)
 
 	case "crew":
 		env["GT_RIG"] = cfg.Rig
 		env["GT_CREW"] = cfg.AgentName
 		env["BD_ACTOR"] = fmt.Sprintf("%s/crew/%s", cfg.Rig, cfg.AgentName)
 		env["GIT_AUTHOR_NAME"] = cfg.AgentName
+		env["GIT_AUTHOR_EMAIL"] = fmt.Sprintf("%s-crew-%s@gastown.local", cfg.Rig, cfg.AgentName)
 	}
 
 	// Only set GT_ROOT if provided

internal/config/env_test.go

@@ -14,6 +14,7 @@ func TestAgentEnv_Mayor(t *testing.T) {
 	assertEnv(t, env, "GT_ROLE", "mayor")
 	assertEnv(t, env, "BD_ACTOR", "mayor")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "mayor")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "mayor@gastown.local")
 	assertEnv(t, env, "GT_ROOT", "/town")
 	assertNotSet(t, env, "GT_RIG")
 	assertNotSet(t, env, "BEADS_NO_DAEMON")
@@ -31,6 +32,7 @@ func TestAgentEnv_Witness(t *testing.T) {
 	assertEnv(t, env, "GT_RIG", "myrig")
 	assertEnv(t, env, "BD_ACTOR", "myrig/witness")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "myrig/witness")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "myrig-witness@gastown.local")
 	assertEnv(t, env, "GT_ROOT", "/town")
 }
 
@@ -49,6 +51,7 @@ func TestAgentEnv_Polecat(t *testing.T) {
 	assertEnv(t, env, "GT_POLECAT", "Toast")
 	assertEnv(t, env, "BD_ACTOR", "myrig/polecats/Toast")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "Toast")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "myrig-polecat-Toast@gastown.local")
 	assertEnv(t, env, "BEADS_AGENT_NAME", "myrig/Toast")
 	assertEnv(t, env, "BEADS_NO_DAEMON", "1")
 }
@@ -68,6 +71,7 @@ func TestAgentEnv_Crew(t *testing.T) {
 	assertEnv(t, env, "GT_CREW", "emma")
 	assertEnv(t, env, "BD_ACTOR", "myrig/crew/emma")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "emma")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "myrig-crew-emma@gastown.local")
 	assertEnv(t, env, "BEADS_AGENT_NAME", "myrig/emma")
 	assertEnv(t, env, "BEADS_NO_DAEMON", "1")
 }
@@ -85,6 +89,7 @@ func TestAgentEnv_Refinery(t *testing.T) {
 	assertEnv(t, env, "GT_RIG", "myrig")
 	assertEnv(t, env, "BD_ACTOR", "myrig/refinery")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "myrig/refinery")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "myrig-refinery@gastown.local")
 	assertEnv(t, env, "BEADS_NO_DAEMON", "1")
 }
 
@@ -98,6 +103,7 @@ func TestAgentEnv_Deacon(t *testing.T) {
 	assertEnv(t, env, "GT_ROLE", "deacon")
 	assertEnv(t, env, "BD_ACTOR", "deacon")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "deacon")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "deacon@gastown.local")
 	assertEnv(t, env, "GT_ROOT", "/town")
 	assertNotSet(t, env, "GT_RIG")
 	assertNotSet(t, env, "BEADS_NO_DAEMON")
@@ -113,6 +119,7 @@ func TestAgentEnv_Boot(t *testing.T) {
 	assertEnv(t, env, "GT_ROLE", "boot")
 	assertEnv(t, env, "BD_ACTOR", "deacon-boot")
 	assertEnv(t, env, "GIT_AUTHOR_NAME", "boot")
+	assertEnv(t, env, "GIT_AUTHOR_EMAIL", "boot@gastown.local")
 	assertEnv(t, env, "GT_ROOT", "/town")
 	assertNotSet(t, env, "GT_RIG")
 	assertNotSet(t, env, "BEADS_NO_DAEMON")