feat: add psagentai agent with deployment and configuration

Initial project setup including the main agent script, configuration
files, profile JSON state, systemd service unit, startup script,
deployment documentation, and Python dependencies.

Includes .env, venv/, and __pycache__/ which should likely be
excluded via .gitignore to avoid committing secrets and artifacts.

venv/lib/python3.11/site-packages/pydantic/experimental/missing_sentinel.py

@@ -0,0 +1,29 @@
+"""Experimental module exposing the `MISSING` sentinel.
+
+!!! warning "Deprecated"
+    The `MISSING` sentinel is no longer experimental, and should be imported from the main `pydantic` module.
+"""
+
+import warnings
+from typing import TYPE_CHECKING, Any
+
+from ..warnings import PydanticDeprecatedSince214
+
+if TYPE_CHECKING:
+    from pydantic_core import MISSING
+
+__all__ = ('MISSING',)
+
+
+def __getattr__(name: str) -> Any:
+    if name == 'MISSING':
+        warnings.warn(
+            'The `MISSING` sentinel is no longer experimental. Import it from the main `pydantic` module instead.',
+            category=PydanticDeprecatedSince214,
+            stacklevel=2,
+        )
+        from pydantic_core import MISSING
+
+        return MISSING
+    else:  # pragma: no cover
+        raise AttributeError(f'module {__name__!r} has no attribute {name!r}')