refactor: Add JSON serialization tags to OCI spec fields

- Add `json` tags for `oci_version` and `no_new_privileges`
- Add `json` tag for `additional_gids` in `User` struct
- Add `json` tags for `typ` in `Rlimit`, `Mount`, `LinuxNamespace`
- Add `json` tags for path and ID mapping fields in `Linux`
- Add `json` tags for `file_mode`, `container_id`, `host_id`

lib/virt/crun/model.v

@@ -3,7 +3,7 @@ module crun
 // OCI Runtime Spec structures that can be directly encoded to JSON
 pub struct Spec {
 pub mut:
-	oci_version string
+	oci_version string @[json: 'ociVersion']
 	platform    Platform
 	process     Process
 	root        Root
@@ -28,14 +28,14 @@ pub mut:
 	cwd               string = '/'
 	capabilities      Capabilities
 	rlimits           []Rlimit
-	no_new_privileges    bool
+	no_new_privileges bool @[json: 'noNewPrivileges']
 }
 
 pub struct User {
 pub mut:
 	uid             u32
 	gid             u32
-	additional_gids []u32
+	additional_gids []u32 @[json: 'additionalGids']
 }
 
 pub struct Capabilities {
@@ -49,7 +49,7 @@ pub mut:
 
 pub struct Rlimit {
 pub mut:
-	typ  string
+	typ  string @[json: 'type']
 	hard u64
 	soft u64
 }
@@ -63,7 +63,7 @@ pub mut:
 pub struct Mount {
 pub mut:
 	destination string
-	typ         string
+	typ         string @[json: 'type']
 	source      string
 	options     []string
 }
@@ -73,15 +73,15 @@ pub mut:
 	namespaces     []LinuxNamespace
 	resources      LinuxResources
 	devices        []LinuxDevice
-	masked_paths    []string
-	readonly_paths  []string
-	uid_mappings    []LinuxIDMapping
-	gid_mappings    []LinuxIDMapping
+	masked_paths   []string         @[json: 'maskedPaths']
+	readonly_paths []string         @[json: 'readonlyPaths']
+	uid_mappings   []LinuxIDMapping @[json: 'uidMappings']
+	gid_mappings   []LinuxIDMapping @[json: 'gidMappings']
 }
 
 pub struct LinuxNamespace {
 pub mut:
-	typ  string
+	typ  string @[json: 'type']
 	path string
 }
 
@@ -124,18 +124,18 @@ pub mut:
 pub struct LinuxDevice {
 pub mut:
 	path      string
-	typ         string
+	typ       string @[json: 'type']
 	major     i64
 	minor     i64
-	file_mode   u32
+	file_mode u32 @[json: 'fileMode']
 	uid       u32
 	gid       u32
 }
 
 pub struct LinuxIDMapping {
 pub mut:
-	container_id u32
-	host_id      u32
+	container_id u32 @[json: 'containerID']
+	host_id      u32 @[json: 'hostID']
 	size         u32
 }