Add Persian (fa) localization and an in-app language picker (#1443)

* Add Persian (fa) localization and an in-app language picker

Persian was the one notable gap in the 29-language catalog. Translate all
381 strings (plus the share extension) with proper plural substitutions,
and register fa in knownRegions.

Settings gains a LANGUAGE section: a picker over every language the bundle
ships (native names via Locale), backed by an AppleLanguages override so
users can run bitchat in a language different from the device's. Localization
resolves at process start, so the picker surfaces a restart note.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Remove unused AppLanguageSettings.currentOverride (Periphery)

AppInfoView reads the override via @AppStorage, so the accessor was dead
code and failed the Periphery CI scan.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: jack <212554440+jackjackbits@users.noreply.github.com>

bitchatShareExtension/Localization/Localizable.xcstrings

@@ -38,6 +38,12 @@
             "comment" : "Fallback title when saving a shared link"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "پیوند اشتراک‌گذاری‌شده"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",
@@ -233,6 +239,12 @@
             "comment" : "Shown when the share payload cannot be encoded"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "کدگذاری پیوند ناموفق بود"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",
@@ -428,6 +440,12 @@
             "comment" : "Shown when provided content cannot be shared"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "محتوای قابل اشتراک‌گذاری وجود ندارد"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",
@@ -623,6 +641,12 @@
             "comment" : "Shown when the share extension receives no content"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "چیزی برای اشتراک‌گذاری نیست"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",
@@ -818,6 +842,12 @@
             "comment" : "Confirmation after successfully sharing a link"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "✓ پیوند در bitchat به اشتراک گذاشته شد"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",
@@ -1013,6 +1043,12 @@
             "comment" : "Confirmation after successfully sharing text"
           }
         },
+        "fa" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "✓ متن در bitchat به اشتراک گذاشته شد"
+          }
+        },
         "fil" : {
           "stringUnit" : {
             "state" : "needs_review",