fix: streaming tool call parsing, error handling, and fake HA state mutation

- Fix Gemini streaming tool call merge bug: multiple tool calls with same
  index but different IDs are now parsed as separate calls instead of
  concatenating names (e.g. ha_call_serviceha_call_service)
- Handle partial results in voice mode: show error and stop continuous
  mode when agent returns partial/failed results with empty response
- Fix error display during streaming TTS: error messages are shown in
  full response box even when streaming box was already opened
- Add duplicate sentence filter in TTS: skip near-duplicate sentences
  from LLM repetition
- Fix fake HA server state mutation: turn_on/turn_off/set_temperature
  correctly update entity states; temperature sensor simulates change
  when thermostat is adjusted

tools/tts_tool.py

@@ -522,6 +522,7 @@ def stream_tts_to_speaker(
         min_sentence_len = 20
         long_flush_len = 100
         queue_timeout = 0.5
+        _spoken_sentences: list[str] = []  # track spoken sentences to skip duplicates
         # Regex to strip complete <think>...</think> blocks from buffer
         _think_block_re = re.compile(r'<think[\s>].*?</think>', flags=re.DOTALL)
 
@@ -532,6 +533,12 @@ def stream_tts_to_speaker(
             cleaned = _strip_markdown_for_tts(sentence).strip()
             if not cleaned:
                 return
+            # Skip duplicate/near-duplicate sentences (LLM repetition)
+            cleaned_lower = cleaned.lower().rstrip(".!,")
+            for prev in _spoken_sentences:
+                if prev.lower().rstrip(".!,") == cleaned_lower:
+                    return
+            _spoken_sentences.append(cleaned)
             # Display raw sentence on screen before TTS processing
             if display_callback is not None:
                 display_callback(sentence)