fix(android/diagnostics): keep uploader drain within ReturnCount gate

drainSafe/drain each had 3 returns (detekt ReturnCount ≤ 2). Collapse the
guard clauses and convert drain's loop to a `more` flag — same behavior,
zero/two returns.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K55iTxn95BtshocgdE1shW

android/app/src/main/java/com/fabledsword/minstrel/diagnostics/DiagnosticsUploader.kt

@@ -70,8 +70,10 @@ class DiagnosticsUploader @Inject constructor(
 
     /** Coalesces concurrent triggers via tryLock — a drain in flight wins. */
     private suspend fun drainSafe() {
-        if (authStore.sessionCookie.value.isNullOrEmpty()) return
-        val clientId = authStore.clientId.value ?: return
+        val clientId = authStore.clientId.value
+        // Signed out / no client id yet → nothing to do. Single guard keeps
+        // the return count within the detekt gate.
+        if (authStore.sessionCookie.value.isNullOrEmpty() || clientId == null) return
         if (!mutex.tryLock()) return
         try {
             drain(clientId)
@@ -81,13 +83,14 @@ class DiagnosticsUploader @Inject constructor(
     }
 
     private suspend fun drain(clientId: String) {
-        while (true) {
+        var more = true
+        while (more) {
             val batch = runCatching { dao.takeBatch(BATCH_SIZE) }.getOrNull().orEmpty()
-            if (batch.isEmpty()) return
-            val sent = runCatching { upload(clientId, batch) }.isSuccess
-            if (!sent) return // leave rows for the next trigger
-            runCatching { dao.deleteByIds(batch.map { it.id }) }
-            if (batch.size < BATCH_SIZE) return
+            val sent = batch.isNotEmpty() && runCatching { upload(clientId, batch) }.isSuccess
+            if (sent) runCatching { dao.deleteByIds(batch.map { it.id }) }
+            // Keep going only while a full batch sent cleanly; otherwise stop
+            // (empty buffer, or a failure to retry on the next trigger).
+            more = sent && batch.size >= BATCH_SIZE
         }
     }