Fix textual-serve web: robust IP detection for WebSocket URL

The landing page wasn't interactive because public_url resolved to
localhost, making WebSocket connections fail from remote browsers.

- Added multiple IP detection methods (socket, hostname -I, gethostbyname)
- Support --port= and --host= flag formats
- Print actual serving URL on startup
- Switch web start back to textual-serve (TUI in browser)

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

bin/gniza

@@ -402,10 +402,10 @@ if [[ "$SUBCOMMAND" == "web" ]]; then
             _web_port="" _web_host=""
             _web_port=$(_parse_flag "--port" "${SUBCMD_ARGS[@]+"${SUBCMD_ARGS[@]}"}") || true
             _web_host=$(_parse_flag "--host" "${SUBCMD_ARGS[@]+"${SUBCMD_ARGS[@]}"}") || true
-            _web_args=()
+            _web_args=(--web)
             [[ -n "$_web_port" ]] && _web_args+=(--port="$_web_port")
             [[ -n "$_web_host" ]] && _web_args+=(--host="$_web_host")
-            PYTHONPATH="$GNIZA_DIR:${PYTHONPATH:-}" exec python3 -m web "${_web_args[@]}"
+            PYTHONPATH="$GNIZA_DIR:${PYTHONPATH:-}" exec python3 -m tui "${_web_args[@]}"
             ;;
         install-service)
             _service_src="$GNIZA_DIR/etc/gniza-web.service"

etc/gniza-web.service

@@ -4,11 +4,9 @@ After=network.target
 
 [Service]
 Type=simple
-ExecStart=/usr/bin/python3 -m web
+ExecStart=/usr/bin/python3 -m tui --web --host 0.0.0.0 --port 8080
 WorkingDirectory=/usr/local/gniza
 Environment=GNIZA_DIR=/usr/local/gniza
-Environment=GNIZA_CONFIG_DIR=/etc/gniza
-Environment=LOG_DIR=/var/log/gniza
 Environment=PYTHONPATH=/usr/local/gniza
 Restart=on-failure
 RestartSec=5

tui/__main__.py

@@ -1,5 +1,6 @@
 import os
 import socket
+import subprocess
 import sys
 from pathlib import Path
 
@@ -11,40 +12,74 @@ _ROOT = os.environ.get("GNIZA_DIR", str(Path(__file__).resolve().parent.parent))
 
 def _get_local_ip() -> str:
     """Get the machine's LAN IP for public_url."""
+    # Method 1: UDP socket trick
     try:
         s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        s.settimeout(2)
         s.connect(("8.8.8.8", 80))
         ip = s.getsockname()[0]
         s.close()
+        if ip and ip != "0.0.0.0":
             return ip
     except Exception:
-        return "localhost"
+        pass
+    # Method 2: hostname -I
+    try:
+        result = subprocess.run(
+            ["hostname", "-I"], capture_output=True, text=True, timeout=5
+        )
+        if result.returncode == 0:
+            ip = result.stdout.strip().split()[0]
+            if ip:
+                return ip
+    except Exception:
+        pass
+    # Method 3: hostname resolution
+    try:
+        return socket.gethostbyname(socket.gethostname())
+    except Exception:
+        return "127.0.0.1"
+
+
+def _parse_web_args():
+    """Parse --port and --host from sys.argv."""
+    port = 8080
+    host = "0.0.0.0"
+    for i, arg in enumerate(sys.argv):
+        if arg.startswith("--port="):
+            port = int(arg.split("=", 1)[1])
+        elif arg == "--port" and i + 1 < len(sys.argv):
+            port = int(sys.argv[i + 1])
+        elif arg.startswith("--host="):
+            host = arg.split("=", 1)[1]
+        elif arg == "--host" and i + 1 < len(sys.argv):
+            host = sys.argv[i + 1]
+    return host, port
 
 
 def main():
     if "--web" in sys.argv:
         from textual_serve.server import Server
-        port = 8080
-        host = "0.0.0.0"
-        public_host = None
-        for i, arg in enumerate(sys.argv):
-            if arg == "--port" and i + 1 < len(sys.argv):
-                port = int(sys.argv[i + 1])
-            elif arg == "--host" and i + 1 < len(sys.argv):
-                host = sys.argv[i + 1]
-                public_host = host
+
+        host, port = _parse_web_args()
+
         os.environ["PYTHONPATH"] = f"{_ROOT}:{os.environ.get('PYTHONPATH', '')}"
         os.environ["GNIZA_DIR"] = _ROOT
-        # textual-serve uses public_url to build WebSocket URLs.
-        # If binding to 0.0.0.0, detect the real IP for the browser.
-        if public_host is None:
-            public_host = _get_local_ip() if host == "0.0.0.0" else host
+
+        # Determine public URL for WebSocket connections
+        if host == "0.0.0.0":
+            public_host = _get_local_ip()
+        else:
+            public_host = host
+
         public_url = f"http://{public_host}:{port}"
+        print(f"GNIZA web: serving TUI at {public_url}")
+
         server = Server(
-            "python3 -m tui",
+            f"python3 -m tui",
             host=host,
             port=port,
-            title="gniza",
+            title="GNIZA Backup",
             public_url=public_url,
         )
         server.serve()