feat: add desktop packaging (pywebview + PyInstaller)

- resource_path.py: frozen/dev path resolution for bundled data files
- app_desktop.py: pywebview entry point (Dash in daemon thread)
- app.spec: PyInstaller onedir config with data files and hidden imports
- Updated queries.py, card_browser.py, app.py to use get_resource_path()
- Added pywebview + pyinstaller to project dependencies
- Fixed unresolved merge conflict in .gitignore
- Removed stale 01_nhs_classic.html and AdditionalAnalytics.md

app_desktop.py

@@ -0,0 +1,62 @@
+"""Desktop entry point: Dash app inside a pywebview native window."""
+
+import sys
+import socket
+import threading
+import time
+from pathlib import Path
+
+# Ensure src/ is on sys.path so that core/, data_processing/, etc. are importable
+_src_dir = str(Path(__file__).resolve().parent / "src")
+if _src_dir not in sys.path:
+    sys.path.insert(0, _src_dir)
+
+import webview
+from dash_app.app import app
+
+
+def find_free_port(start: int = 8050) -> int:
+    """Find the first available port starting from *start*."""
+    for port in range(start, start + 100):
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            try:
+                s.bind(("127.0.0.1", port))
+                return port
+            except OSError:
+                continue
+    raise RuntimeError("No free port found")
+
+
+def wait_for_server(port: int, timeout: float = 30.0) -> None:
+    """Block until the Dash server accepts connections."""
+    deadline = time.monotonic() + timeout
+    while time.monotonic() < deadline:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            if s.connect_ex(("127.0.0.1", port)) == 0:
+                return
+        time.sleep(0.1)
+    raise TimeoutError(f"Server did not start within {timeout}s")
+
+
+def main() -> None:
+    port = find_free_port()
+
+    server_thread = threading.Thread(
+        target=app.run,
+        kwargs={"debug": False, "port": port, "use_reloader": False},
+        daemon=True,
+    )
+    server_thread.start()
+    wait_for_server(port)
+
+    webview.create_window(
+        "NHS Pathway Analysis",
+        f"http://127.0.0.1:{port}",
+        width=1400,
+        height=900,
+    )
+    webview.start()
+
+
+if __name__ == "__main__":
+    main()