feat: major project restructure - move Django to backend dir and fix critical imports

- Restructure project: moved Django backend to backend/ directory
- Add frontend/ directory for future Next.js application
- Add shared/ directory for common resources
- Fix critical Django import errors:
  - Add missing sys.path modification for apps directory
  - Fix undefined CATEGORY_CHOICES imports in rides module
  - Fix media migration undefined references
  - Remove unused imports and f-strings without placeholders
- Install missing django-environ dependency
- Django server now runs without ModuleNotFoundError
- Update .gitignore and README for new structure
- Add pnpm workspace configuration for monorepo setup

static/js/search.js

@@ -1,42 +0,0 @@
-function parkSearch() {
-    return {
-        query: '',
-        results: [],
-        loading: false,
-        selectedId: null,
-        
-        async search() {
-            if (!this.query.trim()) {
-                this.results = [];
-                return;
-            }
-
-            this.loading = true;
-            try {
-                const response = await fetch(`/parks/suggest_parks/?search=${encodeURIComponent(this.query)}`);
-                const data = await response.json();
-                this.results = data.results;
-            } catch (error) {
-                console.error('Search failed:', error);
-                this.results = [];
-            } finally {
-                this.loading = false;
-            }
-        },
-
-        clear() {
-            this.query = '';
-            this.results = [];
-            this.selectedId = null;
-        },
-
-        selectPark(park) {
-            this.query = park.name;
-            this.selectedId = park.id;
-            this.results = [];
-            
-            // Trigger filter update
-            document.getElementById('park-filters').dispatchEvent(new Event('change'));
-        }
-    };
-}