feat: Implement comprehensive geocoding improvements with loading indicators

- Add multi-strategy geocoding fallback system for better address resolution
- Implement loading spinners and visual feedback for all geocoding operations
- Move geocoding messages to venue section for better visibility
- Add dynamic message template system with proper styling
- Optimize backend to trust frontend coordinates and reduce API calls
- Add rate limiting and proper User-Agent headers for Nominatim compliance
- Improve error handling and user feedback throughout geocoding flow

🤖 Generated with [Claude Code](https://claude.ai/code)

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

app/models/event.rb

@@ -23,27 +23,7 @@ class Event < ApplicationRecord
   has_many :orders
 
   # === Callbacks ===
-  before_validation :geocode_address, if: :venue_address_changed?
-
-  # === Instance Methods ===
-
-  # Check if coordinates were successfully geocoded or are fallback coordinates
-  def geocoding_successful?
-    return false if latitude.blank? || longitude.blank?
-
-    # Check if coordinates are exactly the fallback coordinates
-    fallback_lat = 46.603354
-    fallback_lng = 1.888334
-
-    !(latitude == fallback_lat && longitude == fallback_lng)
-  end
-
-  # Get a user-friendly status message about geocoding
-  def geocoding_status_message
-    return nil if geocoding_successful?
-
-    "Les coordonnées exactes n'ont pas pu être déterminées automatiquement. Une localisation approximative a été utilisée."
-  end
+  before_validation :geocode_address, if: :should_geocode_address?
 
   # Validations for Event attributes
   # Basic information
@@ -75,23 +55,79 @@ class Event < ApplicationRecord
   # Scope for published events ordered by start time
   scope :upcoming, -> { published.where("start_time >= ?", Time.current).order(start_time: :asc) }
 
+
+  # === Instance Methods ===
+
+  # Check if coordinates were successfully geocoded or are fallback coordinates
+  def geocoding_successful?
+    coordinates_look_valid?
+  end
+
+  # Get a user-friendly status message about geocoding
+  def geocoding_status_message
+    return nil if geocoding_successful?
+
+    "Les coordonnées exactes n'ont pas pu être déterminées automatiquement. Une localisation approximative a été utilisée."
+  end
+
   private
 
-  # Automatically geocode address to get latitude and longitude
-  def geocode_address
-    return if venue_address.blank?
+  # Determine if we should perform server-side geocoding
+  def should_geocode_address?
+    # Don't geocode if address is blank
+    return false if venue_address.blank?
+    
+    # Don't geocode if we already have valid coordinates (likely from frontend)
+    return false if coordinates_look_valid?
+    
+    # Only geocode if address changed and we don't have coordinates
+    venue_address_changed?
+  end
 
-    # If we already have coordinates and this is an update, try to geocode
-    # If it fails, keep the existing coordinates
+  # Check if the current coordinates look like they were set by frontend geocoding
+  def coordinates_look_valid?
+    return false if latitude.blank? || longitude.blank?
+    
+    lat_f = latitude.to_f
+    lng_f = longitude.to_f
+    
+    # Basic sanity checks for coordinate ranges
+    return false if lat_f < -90 || lat_f > 90
+    return false if lng_f < -180 || lng_f > 180
+    
+    # Check if coordinates are not the default fallback coordinates
+    fallback_lat = 46.603354
+    fallback_lng = 1.888334
+    
+    # Check if coordinates are not exactly 0,0 (common invalid default)
+    return false if lat_f == 0.0 && lng_f == 0.0
+    
+    # Coordinates are valid if they're not exactly the fallback coordinates
+    !(lat_f == fallback_lat && lng_f == fallback_lng)
+  end
+
+  # Automatically geocode address to get latitude and longitude
+  # This only runs when no valid coordinates are provided (fallback for non-JS users)
+  def geocode_address
+    Rails.logger.info "Running server-side geocoding for '#{venue_address}' (no frontend coordinates provided)"
+    
+    # Store original coordinates in case we need to fall back
     original_lat = latitude
     original_lng = longitude
 
     begin
       # Use OpenStreetMap Nominatim API for geocoding
       encoded_address = URI.encode_www_form_component(venue_address.strip)
-      uri = URI("https://nominatim.openstreetmap.org/search?q=#{encoded_address}&format=json&limit=1")
+      uri = URI("https://nominatim.openstreetmap.org/search?q=#{encoded_address}&format=json&limit=1&addressdetails=1")
 
-      response = Net::HTTP.get_response(uri)
+      http = Net::HTTP.new(uri.host, uri.port)
+      http.use_ssl = true
+      
+      request = Net::HTTP::Get.new(uri)
+      request['User-Agent'] = 'AperoNight Event Platform/1.0 (https://aperonight.com)'
+      request['Accept'] = 'application/json'
+      
+      response = http.request(request)
 
       if response.code == "200"
         data = JSON.parse(response.body)
@@ -100,7 +136,7 @@ class Event < ApplicationRecord
           result = data.first
           self.latitude = result["lat"].to_f.round(6)
           self.longitude = result["lon"].to_f.round(6)
-          Rails.logger.info "Geocoded address '#{venue_address}' to coordinates: #{latitude}, #{longitude}"
+          Rails.logger.info "Server-side geocoded '#{venue_address}' to coordinates: #{latitude}, #{longitude}"
           return
         end
       end
@@ -109,7 +145,7 @@ class Event < ApplicationRecord
       handle_geocoding_failure(original_lat, original_lng)
 
     rescue => e
-      Rails.logger.error "Geocoding failed for address '#{venue_address}': #{e.message}"
+      Rails.logger.error "Server-side geocoding failed for '#{venue_address}': #{e.message}"
       handle_geocoding_failure(original_lat, original_lng)
     end
   end