feat(api): implement ChatKit server with MCP integration

.gitignore

@@ -56,4 +56,6 @@ robolearn-interface/
 .env
 .env.local
 
-cookies.txt
+cookies.txt
+
+rag-agent/

packages/api/pyproject.toml

@@ -14,6 +14,10 @@ dependencies = [
     "uvicorn[standard]>=0.32.0",
     "asyncpg>=0.30.0",
     "sqlalchemy[asyncio]>=2.0.0",
+    "python-dotenv>=1.0.0",
+    # ChatKit + OpenAI Agents SDK for chat server
+    "openai-agents>=0.0.9",
+    "openai-chatkit>=1.4.0",
 ]
 
 [project.optional-dependencies]

packages/api/src/taskflow_api/chatkit_store/__init__.py

@@ -0,0 +1,16 @@
+"""
+TaskFlow ChatKit Store Implementation.
+
+Provides PostgreSQL-based Store for ChatKit conversation persistence.
+Adapted from rag-agent/chatkit_store for TaskFlow API.
+"""
+
+from .config import StoreConfig
+from .context import RequestContext
+from .postgres_store import PostgresStore
+
+__all__ = [
+    "StoreConfig",
+    "PostgresStore",
+    "RequestContext",
+]

packages/api/src/taskflow_api/chatkit_store/config.py

@@ -0,0 +1,83 @@
+"""Configuration for TaskFlow ChatKit store."""
+
+from pydantic import Field, field_validator
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class StoreConfig(BaseSettings):
+    """
+    PostgreSQL Store configuration for TaskFlow ChatKit.
+
+    All settings can be overridden via environment variables with the
+    TASKFLOW_CHATKIT_ prefix (e.g., TASKFLOW_CHATKIT_DATABASE_URL).
+    """
+
+    model_config = SettingsConfigDict(
+        env_prefix="TASKFLOW_CHATKIT_",
+        env_file=".env",
+        env_file_encoding="utf-8",
+        case_sensitive=False,
+        extra="ignore",
+    )
+
+    # Database connection
+    database_url: str = Field(
+        ...,
+        description="PostgreSQL connection URL (postgresql+asyncpg://user:pass@host:port/db)",
+    )
+
+    # Connection pool settings
+    pool_size: int = Field(
+        default=20,
+        description="Maximum number of connections in the pool",
+        ge=1,
+        le=100,
+    )
+
+    max_overflow: int = Field(
+        default=10,
+        description="Maximum overflow connections beyond pool_size",
+        ge=0,
+        le=50,
+    )
+
+    pool_timeout: float = Field(
+        default=30.0,
+        description="Seconds to wait before timing out on getting a connection",
+        gt=0,
+    )
+
+    pool_recycle: int = Field(
+        default=3600, description="Seconds after which connections are recycled", ge=300
+    )
+
+    # Query settings
+    statement_timeout: int = Field(
+        default=30000, description="Statement timeout in milliseconds", ge=1000
+    )
+
+    # Schema - use taskflow_chat to isolate from main taskflow schema
+    schema_name: str = Field(default="taskflow_chat", description="Database schema name for tables")
+
+    @field_validator("database_url")
+    @classmethod
+    def validate_database_url(cls, v: str) -> str:
+        """Ensure database URL uses asyncpg driver and fix SSL parameters."""
+        if not v.startswith("postgresql://") and not v.startswith("postgresql+asyncpg://"):
+            raise ValueError("database_url must start with postgresql:// or postgresql+asyncpg://")
+
+        # Convert to asyncpg if needed
+        if v.startswith("postgresql://"):
+            v = v.replace("postgresql://", "postgresql+asyncpg://", 1)
+
+        # Fix SSL parameters for asyncpg
+        if "sslmode=require" in v:
+            v = v.replace("sslmode=require", "ssl=require")
+        elif "sslmode=prefer" in v:
+            v = v.replace("sslmode=prefer", "ssl=prefer")
+        elif "sslmode=allow" in v:
+            v = v.replace("sslmode=allow", "ssl=allow")
+        elif "sslmode=disable" in v:
+            v = v.replace("sslmode=disable", "ssl=disable")
+
+        return v

packages/api/src/taskflow_api/chatkit_store/context.py

@@ -0,0 +1,37 @@
+"""Request context for ChatKit store operations."""
+
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+
+class RequestContext(BaseModel):
+    """
+    Request context passed to all store operations.
+
+    Provides user isolation and optional metadata for access control,
+    logging, and tracing across all store operations.
+    """
+
+    user_id: str | None = Field(
+        ...,
+        description="Unique identifier for the user making the request",
+        min_length=1,
+    )
+
+    organization_id: str | None = Field(
+        default=None, description="Optional organization ID for multi-org tenancy"
+    )
+
+    request_id: str | None = Field(
+        default=None, description="Optional request ID for tracing and logging"
+    )
+
+    metadata: dict[str, Any] = Field(
+        default_factory=dict, description="Additional context metadata"
+    )
+
+    class Config:
+        """Pydantic configuration."""
+
+        frozen = False  # Allow mutation for adding trace info