Add web GUI mode via textual-serve

Run `gniza web` or `gniza --web` to serve the TUI as a web app
on port 8080. Use --port to change. Requires textual-serve.

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

bin/gniza

@@ -431,7 +431,10 @@ run_cli() {
 }
 
 # ── Mode selection ───────────────────────────────────────────
-if [[ -n "$SUBCOMMAND" ]]; then
+if [[ "$SUBCOMMAND" == "web" || " $* " == *" --web "* ]]; then
+    # Web GUI mode
+    PYTHONPATH="$GNIZA_DIR:${PYTHONPATH:-}" exec python3 -m tui --web "$@"
+elif [[ -n "$SUBCOMMAND" ]]; then
     # Explicit subcommand: always CLI
     run_cli
 elif [[ "$FORCE_CLI" == "true" ]]; then

tui/__main__.py

@@ -1,9 +1,20 @@
+import sys
+
 from tui.app import GnizaApp
 
 
 def main():
-    app = GnizaApp()
-    app.run()
+    if "--web" in sys.argv:
+        from textual_serve.server import Server
+        port = 8080
+        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)
+        server.serve()
+    else:
+        app = GnizaApp()
+        app.run()
 
 
 if __name__ == "__main__":