refactor(envelope): rename error.type pruning/strict_mode to command_denied

The envelope's `type` field was leaking implementation terms ("pruning",
"strict_mode") that describe enforcement mechanism rather than the user-
facing semantic. It also duplicated `detail.layer`, and forced consumers
to branch on two values for the same conceptual error ("a command was
denied by policy").

Collapse both into a single semantic type "command_denied". The
enforcement layer ("pruning" / "strict_mode") is preserved in
`detail.layer` so debugging and per-layer diagnostics still work.

cmd/auth/login.go

@@ -50,7 +50,7 @@ For AI agents: this command blocks until the user completes authorization in the
 browser. Run it in the background and retrieve the verification URL from its output.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if mode := f.ResolveStrictMode(cmd.Context()); mode == core.StrictModeBot {
-				return output.ErrWithHint(output.ExitValidation, "strict_mode",
+				return output.ErrWithHint(output.ExitValidation, "command_denied",
 					fmt.Sprintf("strict mode is %q, user login is disabled in this profile", mode),
 					"if the user explicitly wants to switch to user identity, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)")
 			}

cmd/policy_test.go

@@ -117,8 +117,8 @@ max_risk: write
 		t.Fatalf("+delete-doc RunE should return an error")
 	}
 	var exitErr *output.ExitError
-	if !errors.As(err, &exitErr) || exitErr.Detail == nil || exitErr.Detail.Type != "pruning" {
-		t.Fatalf("expected pruning ExitError, got %T %+v", err, err)
+	if !errors.As(err, &exitErr) || exitErr.Detail == nil || exitErr.Detail.Type != "command_denied" {
+		t.Fatalf("expected command_denied ExitError, got %T %+v", err, err)
 	}
 	detail, ok := exitErr.Detail.Detail.(map[string]any)
 	if !ok || detail["reason_code"] != "command_denylisted" {

cmd/prune.go

@@ -79,7 +79,7 @@ func strictModeStubFrom(child *cobra.Command, mode core.StrictMode) *cobra.Comma
 			return nil
 		},
 		RunE: func(cmd *cobra.Command, args []string) error {
-			return output.ErrWithHint(output.ExitValidation, "strict_mode",
+			return output.ErrWithHint(output.ExitValidation, "command_denied",
 				fmt.Sprintf("strict mode is %q, only %s-identity commands are available", mode, mode.ForcedIdentity()),
 				"if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)")
 		},

cmd/root_integration_test.go

@@ -353,7 +353,7 @@ func TestIntegration_StrictModeBot_ProfileOverride_DirectAuthLoginReturnsEnvelop
 	assertEnvelope(t, code, output.ExitValidation, stdout, stderr, output.ErrorEnvelope{
 		OK: false,
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "bot", only bot-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},
@@ -371,7 +371,7 @@ func TestIntegration_StrictModeBot_ProfileOverride_DirectUserShortcutReturnsEnve
 	assertEnvelope(t, code, output.ExitValidation, stdout, stderr, output.ErrorEnvelope{
 		OK: false,
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "bot", only bot-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},
@@ -409,7 +409,7 @@ func TestIntegration_StrictModeUser_ProfileOverride_ShortcutExplicitBotReturnsEn
 		OK:       false,
 		Identity: "bot",
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "user", only user-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},
@@ -428,7 +428,7 @@ func TestIntegration_StrictModeBot_ProfileOverride_ServiceExplicitUserReturnsEnv
 		OK:       false,
 		Identity: "user",
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "bot", only bot-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},
@@ -446,7 +446,7 @@ func TestIntegration_StrictModeUser_ProfileOverride_ServiceBotOnlyMethodReturnsE
 	assertEnvelope(t, code, output.ExitValidation, stdout, stderr, output.ErrorEnvelope{
 		OK: false,
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "user", only user-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},
@@ -465,7 +465,7 @@ func TestIntegration_StrictModeBot_ProfileOverride_APIExplicitUserReturnsEnvelop
 		OK:       false,
 		Identity: "user",
 		Error: &output.ErrDetail{
-			Type:    "strict_mode",
+			Type:    "command_denied",
 			Message: `strict mode is "bot", only bot-identity commands are available`,
 			Hint:    "if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)",
 		},

internal/cmdutil/factory.go

@@ -161,7 +161,7 @@ func (f *Factory) ResolveStrictMode(ctx context.Context) core.StrictMode {
 func (f *Factory) CheckStrictMode(ctx context.Context, as core.Identity) error {
 	mode := f.ResolveStrictMode(ctx)
 	if mode.IsActive() && !mode.AllowsIdentity(as) {
-		return output.ErrWithHint(output.ExitValidation, "strict_mode",
+		return output.ErrWithHint(output.ExitValidation, "command_denied",
 			fmt.Sprintf("strict mode is %q, only %s-identity commands are available", mode, mode.ForcedIdentity()),
 			"if the user explicitly wants to switch policy, see `lark-cli config strict-mode --help` (confirm with the user before switching; switching does NOT require re-bind)")
 	}

internal/hook/install.go

@@ -324,8 +324,9 @@ var stderr = func() interface{ Write(p []byte) (int, error) } {
 //
 // V1 contract: a denial is signalled by the cobra annotation
 // "lark:pruning_denied_layer" being set on the command. The layer
-// value is the error.type ("pruning" / "strict_mode"); the source
-// follows the annotation "lark:pruning_denied_source".
+// value is the enforcement layer ("pruning" / "strict_mode") that
+// gets emitted as detail.layer in the envelope; the source follows
+// the annotation "lark:pruning_denied_source".
 //
 // This indirection lets us avoid an import cycle between hook and
 // pruning packages.

internal/pruning/aggregation_test.go

@@ -180,8 +180,8 @@ func TestApply_runEReturnsExitErrorAndCommandDeniedError(t *testing.T) {
 	if exitErr.Detail == nil {
 		t.Fatalf("ExitError.Detail required for envelope to render")
 	}
-	if exitErr.Detail.Type != "pruning" {
-		t.Errorf("envelope error.type = %q, want pruning", exitErr.Detail.Type)
+	if exitErr.Detail.Type != "command_denied" {
+		t.Errorf("envelope error.type = %q, want command_denied", exitErr.Detail.Type)
 	}
 	// JSON envelope shape: detail.reason_code must be present and
 	// match the closed enum.
@@ -208,8 +208,8 @@ func TestApply_runEReturnsExitErrorAndCommandDeniedError(t *testing.T) {
 	// Envelope round-trip sanity (the actual JSON cmd/root.go would emit).
 	var buf strings.Builder
 	output.WriteErrorEnvelope(&buf, exitErr, "user")
-	if !strings.Contains(buf.String(), `"type": "pruning"`) {
-		t.Errorf("envelope JSON missing type=pruning, got:\n%s", buf.String())
+	if !strings.Contains(buf.String(), `"type": "command_denied"`) {
+		t.Errorf("envelope JSON missing type=command_denied, got:\n%s", buf.String())
 	}
 	if !strings.Contains(buf.String(), `"reason_code": "write_not_allowed"`) {
 		t.Errorf("envelope JSON missing reason_code, got:\n%s", buf.String())

internal/pruning/apply.go

@@ -102,7 +102,7 @@ func installDenyStub(cmd *cobra.Command, path string, d policydecision.Denial) {
 	// Behaviour without this guard (pre-fix): a user yaml rule matching
 	// a strict-mode stub's path would replace the RunE with the pruning
 	// denyStub, hiding the original strict-mode error message AND
-	// re-labelling error.type from "strict_mode" to "pruning".
+	// re-labelling detail.layer from "strict_mode" to "pruning".
 	if cmd.Annotations != nil &&
 		cmd.Annotations[AnnotationDenialLayer] == policydecision.LayerStrictMode {
 		return
@@ -154,15 +154,13 @@ func installDenyStub(cmd *cobra.Command, path string, d policydecision.Denial) {
 			ReasonCode:   denial.ReasonCode,
 			Reason:       denial.Reason,
 		}
-		// Wrap in *output.ExitError so the cmd/root.go envelope writer
-		// emits a JSON envelope. error.type uses denial.Layer ("pruning"
-		// / "strict_mode") to match the design-doc contract. The detail
-		// map carries the closed-enum reason_code plus the structured
-		// fields agents read.
+		// error.type is the user-facing semantic ("a command was denied by
+		// policy"). detail.layer carries the implementation distinction
+		// ("pruning" vs "strict_mode") for debugging.
 		return &output.ExitError{
 			Code: output.ExitValidation,
 			Detail: &output.ErrDetail{
-				Type:    denial.Layer,
+				Type:    "command_denied",
 				Message: cd.Error(),
 				Detail: map[string]any{
 					"path":          cd.Path,