feat(prompt-optimizer): add prompt optimization APIs and database tables

- Added API endpoints for prompt optimization:
  * POST /prompt/sessions: Create a new prompt optimization session
  * GET /prompt/sessions/{session_id}: Retrieve session message history
  * POST /prompt/sessions/{session_id}/messages: Send message and get optimized prompt
  * PUT /prompt/model: Create or update system prompt model configuration

- Added database models for prompt optimization:
  * prompt_opt_session: Stores session metadata
  * prompt_opt_session_history: Stores session message history
  * prompt_opt_message: Stores user and assistant messages
  * prompt_opt_model_config: Stores system prompt model configurations

- Updated service layer to handle message creation, prompt optimization, and variable parsing
- Added corresponding Pydantic schemas for request and response validation

api/app/models/__init__.py

@@ -20,6 +20,7 @@ from .data_config_model import DataConfig
 from .multi_agent_model import MultiAgentConfig, AgentInvocation
 from .workflow_model import WorkflowConfig, WorkflowExecution, WorkflowNodeExecution
 from .retrieval_info import RetrievalInfo
+from .prompt_optimizer_model import PromptOptimizerModelConfig, PromptOptimizerSession, PromptOptimizerSessionHistory
 
 __all__ = [
     "Tenants",
@@ -54,5 +55,8 @@ __all__ = [
     "WorkflowConfig",
     "WorkflowExecution",
     "WorkflowNodeExecution",
-    "RetrievalInfo"
+    "RetrievalInfo",
+    "PromptOptimizerModelConfig",
+    "PromptOptimizerSession",
+    "PromptOptimizerSessionHistory"
 ]

api/app/models/models_model.py

@@ -15,6 +15,25 @@ class ModelType(StrEnum):
     EMBEDDING = "embedding"
     RERANK = "rerank"
 
+    @classmethod
+    def from_str(cls, value: str) -> "ModelType":
+        """
+        Get a ModelType enum instance from a string value.
+
+        Args:
+            value (str): The string representation of the model type.
+
+        Returns:
+            ModelType: The corresponding ModelType enum object.
+
+        Raises:
+            ValueError: If the given value does not match any ModelType.
+        """
+        try:
+            return cls(value)
+        except ValueError:
+            raise ValueError(f"Invalid ModelType: {value}")
+
 
 class ModelProvider(StrEnum):
     """模型提供商枚举"""

api/app/models/prompt_optimizer_model.py

@@ -0,0 +1,176 @@
+import datetime
+import uuid
+from enum import StrEnum
+
+from sqlalchemy import Column, ForeignKey, Text, DateTime, String, Index
+from sqlalchemy.dialects.postgresql import UUID
+
+from app.db import Base
+
+
+class RoleType(StrEnum):
+    """
+    Enumeration of message roles used in prompt optimization conversations.
+
+    This enum standardizes the role identifiers for messages stored in the
+    prompt optimization session history, ensuring consistency across
+    system-generated messages, user inputs, and assistant responses.
+
+    Attributes:
+        SYSTEM (str): Represents system-level instructions or prompts that
+            define the behavior or constraints of the assistant.
+        USER (str): Represents messages originating from the end user.
+        ASSISTANT (str): Represents messages generated by the AI assistant.
+    """
+    SYSTEM = "system"
+    USER = "user"
+    ASSISTANT = "assistant"
+
+
+class PromptOptimizerModelConfig(Base):
+    """
+    Prompt Optimization Model Configuration.
+
+    This table stores system-level prompt configurations for each tenant.
+    The configuration defines the base system prompt used during prompt
+    optimization sessions and serves as a foundational instruction set
+    for the optimization process.
+
+    Each tenant may have one or more model configurations depending on
+    business requirements.
+
+    Table Name:
+        prompt_model_config
+
+    Columns:
+        id (UUID):
+            Primary key. Unique identifier for the prompt model configuration.
+        tenant_id (UUID):
+            Foreign key referencing `tenants.id`.
+            Identifies the tenant that owns this configuration.
+        system_prompt (Text):
+            The system-level prompt used to guide prompt optimization logic.
+        created_at (DateTime):
+            Timestamp indicating when the configuration was created.
+        updated_at (DateTime):
+            Timestamp indicating the last update time of the configuration.
+
+    Usage:
+        - Loaded when initializing a prompt optimization session
+        - Acts as the root system instruction for all subsequent prompts
+    """
+    __tablename__ = "prompt_model_config"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
+    tenant_id = Column(UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=False, comment="Tenant ID")
+    # model_id = Column(UUID(as_uuid=True), nullable=False, comment="Model ID")
+    system_prompt = Column(Text, nullable=False, comment="System Prompt")
+
+    created_at = Column(DateTime, default=datetime.datetime.now, comment="Creation Time")
+    updated_at = Column(DateTime, default=datetime.datetime.now, onupdate=datetime.datetime.now, comment="Update Time")
+
+
+class PromptOptimizerSession(Base):
+    """
+    Prompt Optimization Session Registry.
+
+    This table records high-level metadata for prompt optimization sessions.
+    Each record represents a single logical session initiated by a user
+    under a specific tenant.
+
+    The session acts as a container for multiple conversation messages
+    stored in the session history table.
+
+    Table Name:
+        prompt_opt_session_list
+
+    Columns:
+        id (UUID):
+            Primary key. Internal unique identifier for the session record.
+        tenant_id (UUID):
+            Foreign key referencing `tenants.id`.
+            Identifies the tenant under which the session is created.
+        session_id (UUID):
+            Public-facing session identifier used to group conversation history.
+        user_id (UUID):
+            Foreign key referencing `users.id`.
+            Identifies the user who initiated the session.
+        created_at (DateTime):
+            Timestamp indicating when the session was created.
+
+    Design Notes:
+        - This table intentionally does not store message content
+        - Message-level data is stored in `prompt_opt_session_history`
+        - Enables efficient session listing and pagination
+    """
+    __tablename__ = "prompt_opt_session_list"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
+    tenant_id = Column(UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=False, comment="Tenant ID")
+    # app_id = Column(UUID(as_uuid=True), ForeignKey("apps.id"), nullable=False, comment="Application ID")
+    session_id = Column(UUID(as_uuid=True), nullable=False, comment="Session ID")
+    user_id = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False, comment="User ID")
+
+    created_at = Column(DateTime, default=datetime.datetime.now, comment="Creation Time", index=True)
+
+
+class PromptOptimizerSessionHistory(Base):
+    """
+    Prompt Optimization Session Message History.
+
+    This table stores the complete conversational history of a prompt
+    optimization session, including system prompts, user inputs, and
+    assistant responses.
+
+    Each record represents a single message within a session, preserving
+    the chronological order of interactions.
+
+    Table Name:
+        prompt_opt_session_history
+
+    Columns:
+        id (UUID):
+            Primary key. Unique identifier for the message record.
+        tenant_id (UUID):
+            Foreign key referencing `tenants.id`.
+            Identifies the tenant under which the session operates.
+        session_id (UUID):
+            Logical session identifier linking messages to a session.
+        user_id (UUID):
+            Foreign key referencing `users.id`.
+            Identifies the user associated with the session.
+        message_role (Text):
+            Role of the message sender (e.g., system, user, assistant).
+        message_content (Text):
+            Raw message content generated or provided during the session.
+        prompt (Text):
+            The prompt snapshot used at the time of message generation.
+        created_at (DateTime):
+            Timestamp indicating when the message was created.
+
+    Design Notes:
+        - Supports full conversation replay and audit
+        - Enables prompt evolution tracking over time
+        - Indexed by creation time for efficient chronological queries
+    """
+    __tablename__ = "prompt_opt_session_history"
+
+    __table_args__ = (
+        Index(
+            "ix_prompt_opt_session_history_session_user_created",
+            "session_id",
+            "user_id",
+            "created_at"
+        ),
+    )
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4, index=True)
+    tenant_id = Column(UUID(as_uuid=True), ForeignKey("tenants.id"), nullable=False, comment="Tenant ID")
+    # app_id = Column(UUID(as_uuid=True), ForeignKey("apps.id"), nullable=False, comment="Application ID")
+    session_id = Column(UUID(as_uuid=True), nullable=False, comment="Session ID")
+    user_id = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=False, comment="User ID")
+    role = Column(String, nullable=False, comment="Message Role")
+    content = Column(Text, nullable=False, comment="Message Content")
+    # prompt = Column(Text, nullable=False, comment="Prompt")
+
+    created_at = Column(DateTime, default=datetime.datetime.now, comment="Creation Time", index=True)