feat(i18n): wire ja into build/serve/extract-i18n targets and language selector

apps/client/project.json

@@ -118,6 +118,10 @@
           "baseHref": "/it/",
           "localize": ["it"]
         },
+        "development-ja": {
+          "baseHref": "/ja/",
+          "localize": ["ja"]
+        },
         "development-ko": {
           "baseHref": "/ko/",
           "localize": ["ko"]
@@ -243,6 +247,9 @@
         "development-it": {
           "buildTarget": "client:build:development-it"
         },
+        "development-ja": {
+          "buildTarget": "client:build:development-ja"
+        },
         "development-ko": {
           "buildTarget": "client:build:development-ko"
         },
@@ -282,6 +289,7 @@
           "messages.es.xlf",
           "messages.fr.xlf",
           "messages.it.xlf",
+          "messages.ja.xlf",
           "messages.ko.xlf",
           "messages.nl.xlf",
           "messages.pl.xlf",

apps/client/src/app/components/user-account-settings/user-account-settings.html

@@ -103,6 +103,13 @@
                     >Italiano (<ng-container i18n>Community</ng-container
                     >)</mat-option
                   >
+                  @if (user?.settings?.isExperimentalFeatures) {
+                    <mat-option value="ja"
+                      >Japanese / 日本語 (<ng-container i18n
+                        >Community</ng-container
+                      >)</mat-option
+                    >
+                  }
                   @if (user?.settings?.isExperimentalFeatures) {
                     <mat-option value="ko"
                       >Korean / 한국어 (<ng-container i18n