feat: add sticky error-aware key mastery

Persist ranked-only mastery and use it consistently across progression, milestones, counts, and localized UI. Preserve mastery during history rebuilds, replay errors accurately, and generate replay-derived test profiles. Document the follow-up plan to remove the drill history cap.

src/i18n.rs

@@ -2,8 +2,8 @@ pub use rust_i18n::t;
 
 /// Available UI locale codes. Separate from dictionary language support.
 pub const SUPPORTED_UI_LOCALES: &[&str] = &[
-    "en", "de", "es", "fr", "it", "pt", "nl", "sv", "da", "nb", "fi", "pl", "cs", "ro", "hr",
-    "hu", "lt", "lv", "sl", "et", "tr",
+    "en", "de", "es", "fr", "it", "pt", "nl", "sv", "da", "nb", "fi", "pl", "cs", "ro", "hr", "hu",
+    "lt", "lv", "sl", "et", "tr",
 ];
 
 pub fn set_ui_locale(locale: &str) {
@@ -18,7 +18,11 @@ pub fn set_ui_locale(locale: &str) {
 /// Retrieve the set of all translation keys for a given locale.
 /// Used by the catalog parity test to verify every key exists in every locale.
 #[cfg(test)]
-fn collect_yaml_keys(value: &serde_yaml::Value, prefix: &str, keys: &mut std::collections::BTreeSet<String>) {
+fn collect_yaml_keys(
+    value: &serde_yaml::Value,
+    prefix: &str,
+    keys: &mut std::collections::BTreeSet<String>,
+) {
     match value {
         serde_yaml::Value::Mapping(map) => {
             for (k, v) in map {
@@ -54,9 +58,7 @@ pub fn localized_language_layout_error(
             layout = layout_key
         )
         .to_string(),
-        LanguageBlockedBySupportLevel(key) => {
-            t!("errors.language_blocked", key = key).to_string()
-        }
+        LanguageBlockedBySupportLevel(key) => t!("errors.language_blocked", key = key).to_string(),
     }
 }
 
@@ -67,8 +69,8 @@ mod tests {
 
     fn locale_keys(locale: &str) -> BTreeSet<String> {
         let path = format!("locales/{locale}.yml");
-        let content = std::fs::read_to_string(&path)
-            .unwrap_or_else(|e| panic!("Failed to read {path}: {e}"));
+        let content =
+            std::fs::read_to_string(&path).unwrap_or_else(|e| panic!("Failed to read {path}: {e}"));
         let root: serde_yaml::Value = serde_yaml::from_str(&content)
             .unwrap_or_else(|e| panic!("Failed to parse {path}: {e}"));
         let mut keys = BTreeSet::new();
@@ -111,7 +113,11 @@ mod tests {
             }
         }
 
-        assert!(errors.is_empty(), "Catalog parity errors:\n{}", errors.join("\n"));
+        assert!(
+            errors.is_empty(),
+            "Catalog parity errors:\n{}",
+            errors.join("\n")
+        );
     }
 
     #[test]