Update LLM model to Gemini 2.5 Flash by default

config/cli/limei_default.yaml

@@ -1,5 +1,5 @@
 asr_model: openai/whisper-large-v3-turbo
-llm_model: google/gemma-2-2b
+llm_model: gemini-2.5-flash
 svs_model: espnet/aceopencpop_svs_visinger2_40singer_pretrain
 melody_source: sample-lyric-kising
 language: mandarin

config/cli/yaoyin_default.yaml

@@ -1,5 +1,5 @@
 asr_model: openai/whisper-large-v3-turbo
-llm_model: google/gemma-2-2b
+llm_model: gemini-2.5-flash
 svs_model: espnet/aceopencpop_svs_visinger2_40singer_pretrain
 melody_source: sample-lyric-kising
 language: mandarin

config/interface/default.yaml

@@ -1,5 +1,5 @@
 asr_model: openai/whisper-large-v3-turbo
-llm_model: google/gemma-2-2b
+llm_model: gemini-2.5-flash
 svs_model: espnet/aceopencpop_svs_visinger2_40singer_pretrain
 melody_source: sample-lyric-kising
 language: mandarin

config/interface/options.yaml

@@ -13,6 +13,8 @@ asr_models:
     name: Wav2Vec2-Base-960h
 
 llm_models:
+  - id: gemini-2.5-flash
+    name: Gemini 2.5 Flash
   - id: google/gemma-2-2b
     name: Gemma 2 2B
   - id: MiniMaxAI/MiniMax-M1-80k