fix(server): gracefully degrade when vault is locked during browser search

app/src/main/java/org/searchmob/data/prefs/PersonalizationPreferences.kt

@@ -14,7 +14,7 @@ import org.searchmob.engine.rank.Personalizer
  */
 class PersonalizationPreferences(private val store: PreferencesStore) {
     suspend fun load(): PersonalizationModel {
-        val raw = store.get(KEY) ?: return PersonalizationModel()
+        val raw = runCatching { store.get(KEY) }.getOrNull() ?: return PersonalizationModel()
         return Personalizer.fromJson(raw)
     }
 

app/src/main/java/org/searchmob/data/prefs/RankingPreferences.kt

@@ -16,7 +16,7 @@ import org.searchmob.engine.rank.RankingRules
  */
 class RankingPreferences(private val store: PreferencesStore) {
     suspend fun load(): RankingRules {
-        val raw = store.get(KEY) ?: return withDefaultLenses(RankingRules.EMPTY)
+        val raw = runCatching { store.get(KEY) }.getOrNull() ?: return withDefaultLenses(RankingRules.EMPTY)
         val parsed = runCatching { json.decodeFromString<RankingRules>(raw) }.getOrDefault(RankingRules.EMPTY)
         return withDefaultLenses(parsed)
     }

app/src/test/java/org/searchmob/data/RankingPreferencesTest.kt

@@ -39,6 +39,26 @@ private class FakeRankingStore : PreferencesStore {
     override suspend fun clear() = map.clear()
 }
 
+/** A store that throws on every read, simulating a locked vault (DEK wiped from memory). */
+private class LockedStore : PreferencesStore {
+    private fun locked(): Nothing = error("vault is locked: DEK not present in memory")
+
+    override fun observe(): Flow<Preferences> = locked()
+
+    override suspend fun getAll(): Preferences = locked()
+
+    override suspend fun get(key: String): String? = locked()
+
+    override suspend fun put(
+        key: String,
+        value: String,
+    ) = locked()
+
+    override suspend fun remove(key: String) = locked()
+
+    override suspend fun clear() = locked()
+}
+
 class RankingPreferencesTest {
     @Test
     fun domainRuleSetAndClear() =
@@ -92,4 +112,13 @@ class RankingPreferencesTest {
             val prefs = RankingPreferences(FakeRankingStore())
             assertEquals(false, prefs.importJson("not json"))
         }
+
+    @Test
+    fun loadReturnsEmptyWhenVaultIsLocked() =
+        runTest {
+            val prefs = RankingPreferences(LockedStore())
+            val rules = prefs.load()
+            assertEquals(DEFAULT_SAMPLE_LENSES, rules.lenses)
+            assertTrue(rules.domainRules.isEmpty())
+        }
 }