feat: sort languages in selection menu (#1071)

## Summary

* **What is the goal of this PR?** (e.g., Implements the new feature for
file uploading.)

Currently we are displaying the languages in the order they were added
(as in the `Language` enum). However, as new languages are coming in,
this will quickly be confusing to the users.

But we can't just change the ordering of the enum if we want to respect
bakwards compatibility.

So my proposal is to add a mapping of the alphabetical order of the
languages. I've made it so that it's generated by the `gen_i18n.py`
script, which will be used when a new language is added.


* **What changes are included?**

Added the array from the python script and changed
`LanguageSelectActivity` to use the indices from there. Also commited
the generated `I18nKeys.h`

## Additional Context

* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks,
  specific areas to focus on).

I was wondering if there is a better way to sort it. Currently, it's by
unicode value and Czech and Russian are last, which I don't know it it's
the most intuitive.

The current order is:
`Català, Deutsch, English, Español, Français, Português (Brasil),
Română, Svenska, Čeština, Русский`

---

### AI Usage

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Did you use AI tools to help write this code? _**< PARTIALLY >**_

scripts/gen_i18n.py

@@ -9,7 +9,7 @@ Reads YAML files from a translations directory (one file per language) and gener
 
 Each YAML file must contain:
   _language_name: "Native Name"     (e.g. "Español")
-  _language_code: "ENUM_NAME"       (e.g. "SPANISH")
+  _language_code: "ENUM_NAME"       (e.g. "ES")
   STR_KEY: "translation text"
 
 The English file is the reference. Missing keys in other languages are
@@ -108,7 +108,7 @@ def load_translations(
 ) -> Tuple[List[str], List[str], List[str], Dict[str, List[str]]]:
     """
     Read every YAML file in *translations_dir* and return:
-        language_codes   e.g. ["ENGLISH", "SPANISH", ...]
+        language_codes   e.g. ["EN", "ES", ...]
         language_names   e.g. ["English", "Español", ...]
         string_keys      ordered list of STR_* keys (from English)
         translations     {key: [translation_per_language]}
@@ -131,12 +131,12 @@ def load_translations(
     # Identify the English file (must exist)
     english_file = None
     for name, data in parsed.items():
-        if data.get("_language_code", "").upper() == "ENGLISH":
+        if data.get("_language_code", "").upper() == "EN":
             english_file = name
             break
 
     if english_file is None:
-        raise ValueError("No YAML file with _language_code: ENGLISH found")
+        raise ValueError("No YAML file with _language_code: EN found")
 
     # Order: English first, then by _order metadata (falls back to filename)
     def sort_key(fname: str) -> Tuple[int, int, str]:
@@ -220,7 +220,7 @@ LANG_ABBREVIATIONS = {
     "العربية": "AR", "arabic": "AR",
     "עברית": "HE", "hebrew": "HE",
     "فارسی": "FA", "persian": "FA",
-    "čeština": "CZ",
+    "čeština": "CS",
 }
 
 
@@ -438,6 +438,31 @@ def generate_keys_header(
         "constexpr uint8_t getLanguageCount() "
         "{ return static_cast<uint8_t>(Language::_COUNT); }"
     )
+    lines.append("")
+
+    # Sorted language indices for display order
+    # (English first, then by language code alphabetically)
+    english_idx = languages.index("EN")
+    rest = sorted(
+        (i for i in range(len(languages)) if i != english_idx),
+        key=lambda i: languages[i],
+    )
+    sorted_indices = [english_idx] + rest
+    comment_names = ", ".join(language_names[i] for i in sorted_indices)
+    lines.append("// Sorted language indices by code (auto-generated by gen_i18n.py)")
+    lines.append(f"// Order: {comment_names}")
+    lines.append(
+        "constexpr uint8_t SORTED_LANGUAGE_INDICES[] = {"
+        f"{', '.join(str(i) for i in sorted_indices)}"
+        "};"
+    )
+    lines.append("")
+    lines.append(
+        "static_assert(sizeof(SORTED_LANGUAGE_INDICES) / sizeof(SORTED_LANGUAGE_INDICES[0]) == getLanguageCount(),"
+    )
+    lines.append(
+        '              "SORTED_LANGUAGE_INDICES size mismatch");'
+    )
 
     _write_file(output_path, lines)