Add delete with confirmation for trips and dashcam

- Confirmation modal in server base.html (window.confirmDelete promise helper)
- Trip delete: trash button in Replay column (server-only via data-deletable on
  trip-list div), DELETE /api/v1/portal/trip/<id>, removes computed trip only
  (raw tracking_points kept)
- Dashcam delete: trash button next to download, DELETE /api/v1/portal/dashcam/<id>,
  removes from DB + disk (best-effort file removal)
- history.js: delete button gated on data-deletable='1' attribute; click handler
  intercepts before replay logic
- db.py: delete_trip(), delete_dashcam_file() helpers

Co-authored-by: Copilot <[email protected]>

server/templates/base.html

@@ -106,6 +106,44 @@
     <script src="{{ url_for('static', filename='bootstrap/js/bootstrap.min.js') }}"></script>
     <script src="{{ url_for('static', filename='js/bs-init.js') }}"></script>
     <script src="{{ url_for('static', filename='js/theme.js') }}"></script>
+
+    {# ── Shared confirmation modal ─────────────────────────────────────────── #}
+    <div class="modal fade" id="confirm-modal" tabindex="-1" aria-labelledby="confirm-modal-label" aria-hidden="true">
+        <div class="modal-dialog modal-dialog-centered">
+            <div class="modal-content">
+                <div class="modal-header">
+                    <h5 class="modal-title" id="confirm-modal-label">Confirm delete</h5>
+                    <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
+                </div>
+                <div class="modal-body" id="confirm-modal-body">Are you sure?</div>
+                <div class="modal-footer">
+                    <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Cancel</button>
+                    <button type="button" class="btn btn-danger" id="confirm-modal-ok">Delete</button>
+                </div>
+            </div>
+        </div>
+    </div>
+    <script>
+    // Global helper: show confirmation modal, resolve true/false on user choice.
+    window.confirmDelete = function(message) {
+        return new Promise(function(resolve) {
+            const modal = document.getElementById('confirm-modal');
+            document.getElementById('confirm-modal-body').textContent = message;
+            const bsModal = bootstrap.Modal.getOrCreate(modal);
+            const okBtn = document.getElementById('confirm-modal-ok');
+            function onOk() { cleanup(); resolve(true); }
+            function onHide() { cleanup(); resolve(false); }
+            function cleanup() {
+                okBtn.removeEventListener('click', onOk);
+                modal.removeEventListener('hidden.bs.modal', onHide);
+                bsModal.hide();
+            }
+            okBtn.addEventListener('click', onOk);
+            modal.addEventListener('hidden.bs.modal', onHide, { once: true });
+            bsModal.show();
+        });
+    };
+    </script>
     {% block scripts %}{% endblock %}
 </body>