feat: Add signal handler for synchronizing Incoming edits with StockBatch

## Changes

### 1. Fixed missing signal handler for Incoming edit (inventory/signals.py)
- Added new signal handler `update_stock_batch_on_incoming_edit()` that:
  - Triggers when Incoming is edited (created=False)
  - Synchronizes StockBatch with new quantity and cost_price values
  - Automatically triggers cost price recalculation for the product
  - Updates Stock (inventory balance) for the warehouse
  - Includes proper logging and error handling

### 2. Created IncomingModelForm for editing individual incoming items (inventory/forms.py)
- New ModelForm: `IncomingModelForm` that:
  - Inherits from forms.ModelForm (accepts 'instance' parameter required by UpdateView)
  - Allows editing: product, quantity, cost_price, notes
  - Includes validation for positive quantity and non-negative cost_price
  - Filters only active products

### 3. Updated IncomingUpdateView (inventory/views/incoming.py)
- Changed form_class from IncomingForm to IncomingModelForm
- Updated imports to include IncomingModelForm
- Removed obsolete comments from form_valid method

## Architecture

When editing an Incoming item:
1. User submits form with new quantity/cost_price
2. form.save() triggers post_save signal (created=False)
3. update_stock_batch_on_incoming_edit() synchronizes StockBatch
4. StockBatch.save() triggers update_product_cost_on_batch_change()
5. Product.cost_price is recalculated with weighted average

## Problem Solved

Previously, editing an Incoming item would NOT:
- Update the related StockBatch
- Recalculate product cost_price
- Update warehouse inventory balance
- Maintain data consistency between Incoming and StockBatch

Now all these operations happen automatically through the signal chain.

🤖 Generated with Claude Code

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

myproject/inventory/templates/inventory/warehouse/warehouse_form.html

@@ -47,7 +47,7 @@
                 </label>
                 <textarea class="form-control {% if form.description.errors %}is-invalid{% endif %}"
                           id="{{ form.description.id_for_label }}" name="{{ form.description.html_name }}"
-                          rows="4">{{ form.description.value|default:'' }}</textarea>
+                          rows="3">{{ form.description.value|default:'' }}</textarea>
                 {% if form.description.errors %}
                     <div class="invalid-feedback">
                         {% for error in form.description.errors %}
@@ -57,6 +57,72 @@
                 {% endif %}
             </div>
 
+            <h5 class="mt-4 mb-3">Адрес</h5>
+
+            <div class="row">
+                <div class="col-md-8 mb-3">
+                    <label for="{{ form.street.id_for_label }}" class="form-label">
+                        {{ form.street.label }}
+                    </label>
+                    {{ form.street }}
+                    {% if form.street.errors %}
+                        <div class="invalid-feedback d-block">
+                            {% for error in form.street.errors %}
+                                {{ error }}
+                            {% endfor %}
+                        </div>
+                    {% endif %}
+                </div>
+
+                <div class="col-md-4 mb-3">
+                    <label for="{{ form.building_number.id_for_label }}" class="form-label">
+                        {{ form.building_number.label }}
+                    </label>
+                    {{ form.building_number }}
+                    {% if form.building_number.errors %}
+                        <div class="invalid-feedback d-block">
+                            {% for error in form.building_number.errors %}
+                                {{ error }}
+                            {% endfor %}
+                        </div>
+                    {% endif %}
+                </div>
+            </div>
+
+            <h5 class="mt-4 mb-3">Контакты</h5>
+
+            <div class="row">
+                <div class="col-md-6 mb-3">
+                    <label for="{{ form.phone.id_for_label }}" class="form-label">
+                        {{ form.phone.label }}
+                    </label>
+                    {{ form.phone }}
+                    {% if form.phone.errors %}
+                        <div class="invalid-feedback d-block">
+                            {% for error in form.phone.errors %}
+                                {{ error }}
+                            {% endfor %}
+                        </div>
+                    {% endif %}
+                </div>
+
+                <div class="col-md-6 mb-3">
+                    <label for="{{ form.email.id_for_label }}" class="form-label">
+                        {{ form.email.label }}
+                    </label>
+                    {{ form.email }}
+                    {% if form.email.errors %}
+                        <div class="invalid-feedback d-block">
+                            {% for error in form.email.errors %}
+                                {{ error }}
+                            {% endfor %}
+                        </div>
+                    {% endif %}
+                </div>
+            </div>
+
+            <h5 class="mt-4 mb-3">Настройки</h5>
+
             <div class="mb-3">
                 <div class="form-check">
                     <input type="checkbox" class="form-check-input"
@@ -76,7 +142,21 @@
                     <label class="form-check-label" for="{{ form.is_default.id_for_label }}">
                         {{ form.is_default.label }}
                         <small class="text-muted d-block">
-                            Отмечьте, чтобы использовать этот склад по умолчанию при создании новых документов
+                            {{ form.is_default.help_text }}
+                        </small>
+                    </label>
+                </div>
+            </div>
+
+            <div class="mb-3">
+                <div class="form-check">
+                    <input type="checkbox" class="form-check-input"
+                           id="{{ form.is_pickup_point.id_for_label }}" name="{{ form.is_pickup_point.html_name }}"
+                           {% if form.is_pickup_point.value %}checked{% endif %}>
+                    <label class="form-check-label" for="{{ form.is_pickup_point.id_for_label }}">
+                        {{ form.is_pickup_point.label }}
+                        <small class="text-muted d-block">
+                            {{ form.is_pickup_point.help_text }}
                         </small>
                     </label>
                 </div>