Cut over to agent-core for OpenAI Agent SDK wrapper

OpenAIAgent and supporting helpers moved to the new agent-core
package. This bot now imports them from there instead of carrying
its own copy.

- pyproject.toml: add agent-core as a git dependency, enable
  hatchling allow-direct-references so the build accepts it
- bot/agents.py: deleted (moved to agent-core)
- bot/telegram.py: import OpenAIAgent from agent_core
- bot/config.py: re-export env_flag from agent_core.env so
  existing callers (app.py, tests) keep working
- app.py: import OpenAIAgent from agent_core
- tests/test_agents.py: deleted; the same coverage now lives in
  agent-core's own test suite

Net diff: -800 lines.

Author: John-Lin

app.py

@@ -6,9 +6,9 @@
 import logging
 import sys
 
+from agent_core import OpenAIAgent
 from agents import enable_verbose_stdout_logging
 
-from bot.agents import OpenAIAgent
 from bot.auth import add_group
 from bot.auth import allow_user
 from bot.auth import confirm_pairing

bot/agents.py

@@ -3,25 +3,13 @@
 import os
 from typing import Any
 
+from agent_core.env import env_flag
 from dotenv import find_dotenv
 from dotenv import load_dotenv
 
-logger = logging.getLogger(__name__)
-
-_FALSY_ENV_VALUES = frozenset({"", "0", "false", "no", "off"})
-
+__all__ = ["Configuration", "env_flag"]
 
-def env_flag(name: str) -> bool:
-    """Return True if env var ``name`` is set to a truthy value.
-
-    Common falsy spellings (empty, "0", "false", "no", "off") are treated as
-    disabled so that ``FOO=0`` behaves as users intuitively expect rather than
-    as Python's default "non-empty string is truthy" rule.
-    """
-    raw = os.getenv(name)
-    if raw is None:
-        return False
-    return raw.strip().lower() not in _FALSY_ENV_VALUES
+logger = logging.getLogger(__name__)
 
 
 class Configuration:

bot/config.py

@@ -4,6 +4,7 @@
 import logging
 from collections import deque
 
+from agent_core import OpenAIAgent
 from telegram import Message
 from telegram import Update
 from telegram.constants import ChatAction
@@ -14,7 +15,6 @@
 from telegram.ext import MessageHandler
 from telegram.ext import filters
 
-from .agents import OpenAIAgent
 from .auth import create_pairing_code
 from .auth import get_dm_policy
 from .auth import get_group_config

bot/telegram.py

@@ -5,6 +5,7 @@ description = "Add your description here"
 readme = "README.md"
 requires-python = ">=3.14"
 dependencies = [
+    "agent-core @ git+https://github.com/John-Lin/agent-core.git",
     "mistune-telegram>=0.5.0",
     "openai-agents>=0.13.0",
     "python-dotenv>=1.1.0",
@@ -60,5 +61,8 @@ log_file_level = "INFO"
 log_format = "%(asctime)s %(levelname)s %(message)s"
 log_date_format = "%Y-%m-%d %H:%M:%S"
 
+[tool.hatch.metadata]
+allow-direct-references = true
+
 [tool.hatch.build.targets.wheel]
 packages = ["bot"]