fix(cache): load SQLCipher native lib before every keyed open

The opt-in encrypted cache crash-looped on launch (UnsatisfiedLinkError:
No implementation found for SQLiteConnection.nativeOpen) on any cold start
after encryption was enabled — reported after an app upgrade.

System.loadLibrary("sqlcipher") was only invoked as a side effect of an
actual plaintext<->encrypted conversion (DatabaseEncryption.migrate) or the
one-time #111 account migration. On a steady-state start the cache is
already encrypted and the account migration is already done, so both no-op
and nothing loads the native library before Room opens the keyed database
via SupportOpenHelperFactory -> nativeOpen. The previous process survived
only because an earlier conversion had loaded the .so in-memory; the next
cold start (e.g. an upgrade) crashes.

Load the library explicitly in DatabaseProvisioner whenever it commits to an
encrypted open (idempotent; no-ops when already loaded). Add regression
assertions: the encrypted path must load it, the plaintext path must not.

Verified on a Pixel 10 Pro XL — an in-place update preserving the already-
encrypted cache now launches to the mailbox instead of crash-looping.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/kotlin/org/libremail/data/local/DatabaseProvisioner.kt

@@ -120,6 +120,13 @@ class DatabaseProvisioner internal constructor(
             settings.encryptCache -> {
                 val passphrase = keyStore.resolvePassphrase(appLock)
                 DatabaseEncryption.ensureEncrypted(dbFile, passphrase)
+                // Room is about to open the cache with SQLCipher (SupportOpenHelperFactory), so its
+                // native library must already be loaded. ensureEncrypted() above loads it only as a
+                // side effect of an actual plaintext -> encrypted conversion; on a steady-state start
+                // (cache already encrypted, nothing to convert) that no-ops, so without this explicit
+                // load the keyed open reaches SQLiteConnection.nativeOpen with no library loaded and
+                // crashes with UnsatisfiedLinkError on every cold start once encryption is enabled.
+                DatabaseEncryption.ensureNativeLibraryLoaded()
                 CacheOpenMode.Encrypted(passphrase)
             }
 

app/src/test/kotlin/org/libremail/data/local/DatabaseProvisionerTest.kt

@@ -61,6 +61,7 @@ class DatabaseProvisionerTest {
         every { DatabaseEncryption.isEncrypted(any()) } returns false
         every { DatabaseEncryption.ensureEncrypted(any(), any()) } just Runs
         every { DatabaseEncryption.ensurePlaintext(any(), any()) } just Runs
+        every { DatabaseEncryption.ensureNativeLibraryLoaded() } just Runs
         every { settingsRepository.settings } returns flowOf(AppSettings())
 
         coEvery { keyStore.isClearPending() } returns false
@@ -89,6 +90,11 @@ class DatabaseProvisionerTest {
         coVerify(exactly = 1) { keyStore.resolvePassphrase(false) }
         verify(exactly = 1) { DatabaseEncryption.ensureEncrypted(any(), PASSPHRASE) }
         verify(exactly = 0) { DatabaseEncryption.ensurePlaintext(any(), any()) }
+        // Regression (crash-on-launch after upgrade): the encrypted open path MUST load SQLCipher's
+        // native library itself. ensureEncrypted no-ops when the cache is already encrypted, so if the
+        // load only rode on that conversion, Room's keyed open would hit nativeOpen with no .so loaded
+        // and throw UnsatisfiedLinkError on every cold start.
+        verify(exactly = 1) { DatabaseEncryption.ensureNativeLibraryLoaded() }
     }
 
     @Test
@@ -143,6 +149,9 @@ class DatabaseProvisionerTest {
         coVerify(exactly = 0) { keyStore.resolvePassphrase(any()) }
         verify(exactly = 0) { DatabaseEncryption.ensureEncrypted(any(), any()) }
         verify(exactly = 0) { DatabaseEncryption.ensurePlaintext(any(), any()) }
+        // A plaintext cache opens with the framework helper, never SQLCipher, so it must not touch the
+        // native library — the counterpart to the encrypted path's mandatory load above.
+        verify(exactly = 0) { DatabaseEncryption.ensureNativeLibraryLoaded() }
     }
 
     @Test