Add core data structures for Buildings and Rooms (v0.1.0)

Phase 1 implementation includes:
- Custom Post Type: Buildings with address, contact, and details meta
- Custom Post Type: Rooms with building relationship and gallery
- Custom Taxonomy: Room Types (hierarchical)
- Custom Taxonomy: Amenities (non-hierarchical with icons)
- Admin columns, filters, and status badges
- Gallery meta box with media library integration

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

assets/css/admin.css

@@ -79,3 +79,115 @@
 .submit .button {
 	margin: 0;
 }
+
+/* Room Gallery */
+.bnb-gallery-container {
+	padding: 10px 0;
+}
+
+.bnb-gallery-images {
+	display: flex;
+	flex-wrap: wrap;
+	gap: 10px;
+	margin-bottom: 15px;
+}
+
+.bnb-gallery-image {
+	position: relative;
+	width: 100px;
+	height: 100px;
+	border: 1px solid #c3c4c7;
+	border-radius: 4px;
+	overflow: hidden;
+	cursor: move;
+}
+
+.bnb-gallery-image img {
+	width: 100%;
+	height: 100%;
+	object-fit: cover;
+}
+
+.bnb-gallery-image .bnb-remove-image {
+	position: absolute;
+	top: 2px;
+	right: 2px;
+	width: 20px;
+	height: 20px;
+	padding: 0;
+	border: none;
+	border-radius: 50%;
+	background: rgba(0, 0, 0, 0.7);
+	color: #fff;
+	font-size: 14px;
+	line-height: 18px;
+	text-align: center;
+	cursor: pointer;
+	opacity: 0;
+	transition: opacity 0.2s;
+}
+
+.bnb-gallery-image:hover .bnb-remove-image {
+	opacity: 1;
+}
+
+.bnb-gallery-image .bnb-remove-image:hover {
+	background: #d63638;
+}
+
+/* Status Badge */
+.bnb-status-badge {
+	display: inline-block;
+	padding: 3px 8px;
+	border-radius: 3px;
+	color: #fff;
+	font-size: 12px;
+	font-weight: 600;
+	text-transform: uppercase;
+}
+
+/* Room Details Meta Box */
+#bnb_room_details .form-table td label {
+	display: inline-block;
+	min-width: 100px;
+}
+
+/* Building Details Meta Box */
+#bnb_building_details p {
+	margin: 10px 0;
+}
+
+#bnb_building_details label {
+	display: block;
+	margin-bottom: 5px;
+	font-weight: 600;
+}
+
+#bnb_building_details input {
+	width: 100%;
+}
+
+/* Admin Columns */
+.column-city,
+.column-country,
+.column-room_number,
+.column-capacity,
+.column-status {
+	width: 100px;
+}
+
+.column-building {
+	width: 150px;
+}
+
+.column-rooms {
+	width: 80px;
+}
+
+/* Dashicons in columns */
+.column-capacity .dashicons {
+	color: #646970;
+	font-size: 16px;
+	vertical-align: middle;
+	margin-right: 3px;
+}