Refactor backend to support interface-definition driven model resources

- Introduce a new model structure for managing interface definitions and model resources, enhancing the backend's capability to handle various service integrations.
- Update the Makefile to reflect changes in database seeding and resource management commands.
- Remove the deprecated credentials management routes and replace them with a unified model registry API.
- Modify existing routes and schemas to align with the new model structure, ensuring seamless integration with the frontend.
- Enhance database seeding scripts to populate new model resources and their configurations.
- Update README documentation to reflect the new architecture and usage instructions for model resources and interface definitions.

backend/db/seed_model_resources.sql

@@ -0,0 +1,48 @@
+-- 模型资源种子数据。依赖应用启动时写入 interface_definitions。
+
+INSERT INTO model_resources
+  (id, name, capability, interface_type, values, secrets, enabled, is_default)
+VALUES
+  ('model_001', 'DeepSeek-Chat', 'LLM', 'openai-llm',
+   '{"modelId":"deepseek-chat","apiUrl":"https://api.deepseek.com/v1","temperature":0.7}',
+   '{"apiKey":"replace-me"}', TRUE, TRUE),
+  ('model_002', 'SiliconFlow-TeleSpeechASR', 'ASR', 'openai-asr',
+   '{"modelId":"TeleAI/TeleSpeechASR","apiUrl":"https://api.siliconflow.cn/v1","language":"zh"}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+  ('model_003', 'SiliconFlow-Qwen3-Embedding-4B', 'Embedding', 'openai-embedding',
+   '{"modelId":"Qwen/Qwen3-Embedding-4B","apiUrl":"https://api.siliconflow.cn/v1"}',
+   '{"apiKey":"replace-me"}', TRUE, TRUE),
+  ('model_004', 'SiliconFlow-CosyVoice2-0.5B', 'TTS', 'openai-tts',
+   '{"modelId":"FunAudioLLM/CosyVoice2-0.5B","apiUrl":"https://api.siliconflow.cn/v1","voice":"FunAudioLLM/CosyVoice2-0.5B:anna","speed":1.0,"sourceSampleRate":24000}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+  ('model_005', '讯飞语音识别', 'ASR', 'xfyun-asr',
+   '{"apiUrl":"https://iat-api.xfyun.cn/v2/iat","language":"zh_cn","domain":"iat","accent":"mandarin","dynamicCorrection":false,"frameSize":1280}',
+   '{"appId":"replace-me","apiKey":"replace-me","apiSecret":"replace-me"}', TRUE, TRUE),
+  ('model_006', 'Paraformer 识别', 'ASR', 'dashscope-asr',
+   '{"modelId":"paraformer-realtime-v2","apiUrl":"https://dashscope.aliyuncs.com/api/v1/services/audio/asr","language":"zh"}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+  ('model_007', '讯飞语音合成', 'TTS', 'xfyun-tts',
+   '{"apiUrl":"https://tts-api.xfyun.cn/v2/tts","voice":"xiaoyan","speed":50,"volume":50,"pitch":50,"sourceSampleRate":16000}',
+   '{"appId":"replace-me","apiKey":"replace-me","apiSecret":"replace-me"}', TRUE, TRUE),
+  ('model_008', 'CosyVoice 合成', 'TTS', 'dashscope-tts',
+   '{"modelId":"cosyvoice-v1","apiUrl":"https://dashscope.aliyuncs.com/api/v1/services/audio/tts","voice":"longxiaochun"}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+  ('model_009', 'GPT Realtime', 'Realtime', 'openai-realtime',
+   '{"modelId":"gpt-4o-realtime-preview","apiUrl":"https://api.openai.com/v1/realtime"}',
+   '{"apiKey":"replace-me"}', TRUE, TRUE),
+  ('model_010', 'Gemini Live', 'Realtime', 'gemini-realtime',
+   '{"modelId":"gemini-2.0-flash-live","apiUrl":"https://generativelanguage.googleapis.com/v1beta"}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE),
+  ('model_011', 'text-embedding-3', 'Embedding', 'openai-embedding',
+   '{"modelId":"text-embedding-3-small","apiUrl":"https://api.openai.com/v1/embeddings"}',
+   '{"apiKey":"replace-me"}', TRUE, FALSE)
+ON CONFLICT (id) DO UPDATE SET
+  name = EXCLUDED.name,
+  capability = EXCLUDED.capability,
+  interface_type = EXCLUDED.interface_type,
+  values = EXCLUDED.values,
+  secrets = EXCLUDED.secrets,
+  enabled = EXCLUDED.enabled,
+  is_default = EXCLUDED.is_default,
+  updated_at = now();