Fix web GUI by setting PYTHONPATH in spawned command

textual-serve spawns the app as a subprocess which doesn't
inherit PYTHONPATH. Bake the project root into the command.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tui/__main__.py

@@ -1,7 +1,12 @@
+import os
 import sys
+from pathlib import Path
 
 from tui.app import GnizaApp
 
+# Resolve project root (parent of tui/)
+_PROJECT_ROOT = str(Path(__file__).resolve().parent.parent)
+
 
 def main():
     if "--web" in sys.argv:
@@ -10,7 +15,9 @@ def main():
         for i, arg in enumerate(sys.argv):
             if arg == "--port" and i + 1 < len(sys.argv):
                 port = int(sys.argv[i + 1])
-        server = Server("python3 -m tui", host="0.0.0.0", port=port)
+        env_path = f"{_PROJECT_ROOT}:{os.environ.get('PYTHONPATH', '')}"
+        cmd = f"PYTHONPATH={env_path} GNIZA_DIR={_PROJECT_ROOT} python3 -m tui"
+        server = Server(cmd, host="0.0.0.0", port=port)
         server.serve()
     else:
         app = GnizaApp()