pipeline: zero-init qenc_host_ready, value-init PipelineTTS

The lazy-init flag started on stack garbage. When non-zero the encode
path skipped the codebook load and silently returned empty RVQ codes.

src/pipeline-codec.cpp

@@ -19,8 +19,9 @@
 #include <vector>
 
 bool pipeline_codec_load(PipelineCodec * pc, const char * gguf_path, BackendPair bp) {
-    pc->bp      = bp;
-    pc->backend = bp.backend;
+    pc->bp              = bp;
+    pc->backend         = bp.backend;
+    pc->qenc_host_ready = false;
 
     if (!gf_load(&pc->gguf, gguf_path)) {
         qt_log(QT_LOG_ERROR, "[Pipeline] failed to load %s", gguf_path);

tools/qwen-tts.cpp

@@ -209,7 +209,7 @@ static bool parse_args(int argc, char ** argv, Args & a) {
 static int run(const Args & a) {
     BackendPair bp = backend_init("Talker");
 
-    PipelineTTS pt;
+    PipelineTTS pt = {};
     if (!pipeline_tts_load(&pt, a.model, a.codec, bp)) {
         backend_release(bp.backend, bp.cpu_backend);
         return 1;