feat: implement OpenAI-compatible Realtime API with authentication and management features

- Added support for public Realtime API, including new routes for managing API keys and handling WebRTC connections.
- Introduced RealtimeApiKey model and associated CRUD operations for admin management of API keys.
- Implemented authentication mechanisms for API keys and client secrets.
- Enhanced environment configuration with new secrets for Realtime API.
- Created OpenAIRealtime session management and event processing for real-time interactions.
- Updated schemas and settings to accommodate new features and ensure compatibility with existing systems.

backend/schemas.py

@@ -7,7 +7,7 @@ JSON 用 camelCase(modelId/interfaceType/apiUrl/apiKey),Python 内部用 snake_c
 
 from __future__ import annotations
 
-from datetime import datetime
+from datetime import UTC, datetime
 import re
 from typing import Annotated, Any, Literal, Union
 
@@ -601,3 +601,39 @@ class AnalysisWebhookTestOut(CamelModel):
     latency_ms: int | None = None
     message: str
     payload: dict[str, Any]
+
+
+# ---------- Realtime API keys ----------
+class RealtimeApiKeyCreate(CamelModel):
+    name: str = Field(min_length=1, max_length=128)
+    expires_at: datetime | None = None
+
+    @field_validator("name", mode="before")
+    @classmethod
+    def normalize_name(cls, value: object) -> object:
+        return value.strip() if isinstance(value, str) else value
+
+    @field_validator("expires_at")
+    @classmethod
+    def validate_expiry(cls, value: datetime | None) -> datetime | None:
+        if value is None:
+            return None
+        normalized = value if value.tzinfo else value.replace(tzinfo=UTC)
+        if normalized <= datetime.now(UTC):
+            raise ValueError("expires_at 必须晚于当前时间")
+        return normalized
+
+
+class RealtimeApiKeyOut(CamelModel):
+    id: str
+    name: str
+    key_prefix: str
+    status: Literal["active", "expired", "revoked"]
+    expires_at: datetime | None = None
+    last_used_at: datetime | None = None
+    revoked_at: datetime | None = None
+    created_at: datetime
+
+
+class RealtimeApiKeyCreated(RealtimeApiKeyOut):
+    key: str