Add Agent Bridge addon

Agent Bridge embeds a control bridge in a running Gramps session so an AI
agent can drive the live application: read and modify the tree, operate the
UI, and create and load plugins on the fly.

It ships an MCP (Model Context Protocol) server so any MCP-capable AI can
drive Gramps through standard tools. The gramplet polls a watched control
directory on the GTK main thread and executes submitted Python in a
persistent namespace with dbstate, db, uistate, gui and gramps_lib bound;
the MCP server is a thin stdio adapter over that directory. No network port
is opened.

As defense-in-depth, every request must carry a shared secret token. The
gramplet generates it on first run at ~/.gramps_agent/token (owner-only) and
refuses any request without it; the MCP server and the debug CLI read the
same file automatically. GRAMPS_AGENT_TOKEN overrides the file.

Author: brianmcaudill

AgentBridge/AgentBridge.gpr.py

@@ -0,0 +1,52 @@
+#
+# Gramps - a GTK+/GNOME based genealogy program
+#
+# Copyright (C) 2026  Brian Caudill
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+#
+
+# ------------------------------------------------------------------------
+#
+# Register the Agent Bridge gramplet
+#
+# ------------------------------------------------------------------------
+register(
+    GRAMPLET,
+    id="Agent Bridge",
+    name=_("Agent Bridge"),
+    description=_(
+        "Embeds a control bridge in Gramps so an AI agent can drive the live "
+        "application through a watched directory or an MCP server. Executes "
+        "submitted Python on the GTK main thread. For developers and power "
+        "users; runs arbitrary code at your privileges."
+    ),
+    version="0.0.1",
+    gramps_target_version="6.0",
+    status=STABLE,
+    audience=DEVELOPER,
+    fname="AgentBridge.py",
+    gramplet="AgentBridge",
+    gramplet_title=_("Agent Bridge"),
+    height=140,
+    expand=True,
+    detached_width=520,
+    detached_height=300,
+    navtypes=["Dashboard"],
+    authors=["Brian Caudill"],
+    authors_email=["brian.m.caudill@gmail.com"],
+    maintainers=["Brian Caudill"],
+    maintainers_email=["brian.m.caudill@gmail.com"],
+    help_url="Addon:AgentBridge",
+)