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/lxml/html/_setmixin.py

@@ -0,0 +1,56 @@
+try:
+    from collections.abc import MutableSet
+except ImportError:
+    from collections.abc import MutableSet
+
+
+class SetMixin(MutableSet):
+
+    """
+    Mix-in for sets.  You must define __iter__, add, remove
+    """
+
+    def __len__(self):
+        length = 0
+        for item in self:
+            length += 1
+        return length
+
+    def __contains__(self, item):
+        for has_item in self:
+            if item == has_item:
+                return True
+        return False
+
+    issubset = MutableSet.__le__
+    issuperset = MutableSet.__ge__
+
+    union = MutableSet.__or__
+    intersection = MutableSet.__and__
+    difference = MutableSet.__sub__
+    symmetric_difference = MutableSet.__xor__
+
+    def copy(self):
+        return set(self)
+
+    def update(self, other):
+        self |= other
+
+    def intersection_update(self, other):
+        self &= other
+
+    def difference_update(self, other):
+        self -= other
+
+    def symmetric_difference_update(self, other):
+        self ^= other
+
+    def discard(self, item):
+        try:
+            self.remove(item)
+        except KeyError:
+            pass
+
+    @classmethod
+    def _from_iterable(cls, it):
+        return set(it)