Add granular role grant/revoke endpoints to REST and gRPC APIs

- Add POST /v1/accounts/{id}/roles and DELETE /v1/accounts/{id}/roles/{role} REST endpoints
- Add GrantRole and RevokeRole RPCs to AccountService in gRPC API
- Update OpenAPI specification with new endpoints
- Add grant and revoke subcommands to mciasctl
- Add grant and revoke subcommands to mciasgrpcctl
- Regenerate proto files with new message types and RPCs
- Implement gRPC server methods for granular role management
- All existing tests pass; build verified with goimports
Security: Role changes are audited via EventRoleGranted and EventRoleRevoked events,
consistent with existing SetRoles implementation.

cmd/mciasctl/main.go

@@ -28,6 +28,8 @@
 //
 //	role list   -id UUID
 //	role set    -id UUID -roles role1,role2,...
+//	role grant  -id UUID -role ROLE
+//	role revoke -id UUID -role ROLE
 //
 //	token issue  -id UUID
 //	token revoke -jti JTI
@@ -386,13 +388,17 @@ func (c *controller) accountSetPassword(args []string) {
 
 func (c *controller) runRole(args []string) {
 	if len(args) == 0 {
-		fatalf("role requires a subcommand: list, set")
+		fatalf("role requires a subcommand: list, set, grant, revoke")
 	}
 	switch args[0] {
 	case "list":
 		c.roleList(args[1:])
 	case "set":
 		c.roleSet(args[1:])
+	case "grant":
+		c.roleGrant(args[1:])
+	case "revoke":
+		c.roleRevoke(args[1:])
 	default:
 		fatalf("unknown role subcommand %q", args[0])
 	}
@@ -437,6 +443,41 @@ func (c *controller) roleSet(args []string) {
 	fmt.Printf("roles set: %v\n", roles)
 }
 
+func (c *controller) roleGrant(args []string) {
+	fs := flag.NewFlagSet("role grant", flag.ExitOnError)
+	id := fs.String("id", "", "account UUID (required)")
+	role := fs.String("role", "", "role name (required)")
+	_ = fs.Parse(args)
+
+	if *id == "" {
+		fatalf("role grant: -id is required")
+	}
+	if *role == "" {
+		fatalf("role grant: -role is required")
+	}
+
+	body := map[string]string{"role": *role}
+	c.doRequest("POST", "/v1/accounts/"+*id+"/roles", body, nil)
+	fmt.Printf("role granted: %s\n", *role)
+}
+
+func (c *controller) roleRevoke(args []string) {
+	fs := flag.NewFlagSet("role revoke", flag.ExitOnError)
+	id := fs.String("id", "", "account UUID (required)")
+	role := fs.String("role", "", "role name (required)")
+	_ = fs.Parse(args)
+
+	if *id == "" {
+		fatalf("role revoke: -id is required")
+	}
+	if *role == "" {
+		fatalf("role revoke: -role is required")
+	}
+
+	c.doRequest("DELETE", "/v1/accounts/"+*id+"/roles/"+*role, nil, nil)
+	fmt.Printf("role revoked: %s\n", *role)
+}
+
 // ---- token subcommands ----
 
 func (c *controller) runToken(args []string) {

cmd/mciasgrpcctl/main.go

@@ -28,8 +28,10 @@
 //	account update -id UUID -status active|inactive
 //	account delete -id UUID
 //
-//	role list  -id UUID
-//	role set   -id UUID -roles role1,role2,...
+//	role list   -id UUID
+//	role set    -id UUID -roles role1,role2,...
+//	role grant  -id UUID -role ROLE
+//	role revoke -id UUID -role ROLE
 //
 //	token validate -token TOKEN
 //	token issue    -id UUID
@@ -392,13 +394,17 @@ func (c *controller) accountDelete(args []string) {
 
 func (c *controller) runRole(args []string) {
 	if len(args) == 0 {
-		fatalf("role requires a subcommand: list, set")
+		fatalf("role requires a subcommand: list, set, grant, revoke")
 	}
 	switch args[0] {
 	case "list":
 		c.roleList(args[1:])
 	case "set":
 		c.roleSet(args[1:])
+	case "grant":
+		c.roleGrant(args[1:])
+	case "revoke":
+		c.roleRevoke(args[1:])
 	default:
 		fatalf("unknown role subcommand %q", args[0])
 	}
@@ -455,6 +461,54 @@ func (c *controller) roleSet(args []string) {
 	fmt.Printf("roles set: %v\n", roles)
 }
 
+func (c *controller) roleGrant(args []string) {
+	fs := flag.NewFlagSet("role grant", flag.ExitOnError)
+	id := fs.String("id", "", "account UUID (required)")
+	role := fs.String("role", "", "role name (required)")
+	_ = fs.Parse(args)
+
+	if *id == "" {
+		fatalf("role grant: -id is required")
+	}
+	if *role == "" {
+		fatalf("role grant: -role is required")
+	}
+
+	cl := mciasv1.NewAccountServiceClient(c.conn)
+	ctx, cancel := c.callCtx()
+	defer cancel()
+
+	_, err := cl.GrantRole(ctx, &mciasv1.GrantRoleRequest{Id: *id, Role: *role})
+	if err != nil {
+		fatalf("role grant: %v", err)
+	}
+	fmt.Printf("role granted: %s\n", *role)
+}
+
+func (c *controller) roleRevoke(args []string) {
+	fs := flag.NewFlagSet("role revoke", flag.ExitOnError)
+	id := fs.String("id", "", "account UUID (required)")
+	role := fs.String("role", "", "role name (required)")
+	_ = fs.Parse(args)
+
+	if *id == "" {
+		fatalf("role revoke: -id is required")
+	}
+	if *role == "" {
+		fatalf("role revoke: -role is required")
+	}
+
+	cl := mciasv1.NewAccountServiceClient(c.conn)
+	ctx, cancel := c.callCtx()
+	defer cancel()
+
+	_, err := cl.RevokeRole(ctx, &mciasv1.RevokeRoleRequest{Id: *id, Role: *role})
+	if err != nil {
+		fatalf("role revoke: %v", err)
+	}
+	fmt.Printf("role revoked: %s\n", *role)
+}
+
 // ---- token subcommands ----
 
 func (c *controller) runToken(args []string) {