fix: update custom fields in DocumentGenerator and DOCX_TEMPLATES_README for better usability

DOCX_TEMPLATES_README.md

@@ -49,11 +49,16 @@ This system allows you to generate DOCX documents by filling templates with proj
 #### Financial
 - `{wartosc_zlecenia}`, `{wartosc_zlecenia_1}`, `{wartosc_zlecenia_2}` - Contract value
 
-#### Contacts
-- `{contacts}` - Array of contacts (use loops in advanced templates)
-- `{primary_contact}` - Primary contact name
-- `{primary_contact_phone}` - Primary contact phone
-- `{primary_contact_email}` - Primary contact email
+#### Standard Custom Fields (Pre-filled but Editable)
+- `{zk}` - ZK field
+- `{nr_zk}` - ZK number
+- `{kabel}` - Cable information
+- `{dlugosc}` - Length
+- `{data_wykonania}` - Execution date
+- `{st_nr}` - Station number
+- `{obw}` - Circuit
+- `{wp_short}` - Short WP reference
+- `{plomba}` - Seal/plomb information
 
 ## Example Template Content
 
@@ -78,6 +83,17 @@ Meeting Notes: {meeting_notes}
 Special Instructions: {special_instructions}
 Additional Comments: {additional_comments}
 
+Technical Details:
+ZK: {zk}
+ZK Number: {nr_zk}
+Cable: {kabel}
+Length: {dlugosc}
+Execution Date: {data_wykonania}
+Station Number: {st_nr}
+Circuit: {obw}
+WP Short: {wp_short}
+Seal: {plomba}
+
 Primary Contact:
 Name: {primary_contact}
 Phone: {primary_contact_phone}
@@ -100,7 +116,7 @@ Generated on: {today_date}
 2. In the sidebar, find the "Generate Document" section
 3. Select a template from the dropdown
 4. **Optional**: Click "Pokaż dodatkowe pola" to add custom data
-5. Add any custom fields you need (e.g., `custom_note`, `additional_info`)
+5. Fill in the standard fields (zk, nr_zk, kabel, etc.) and any additional custom fields
 6. Click "Generate Document"
 7. The filled document will be downloaded automatically with filename: `{template_name}_{project_name}_{timestamp}.docx`
 
@@ -108,10 +124,16 @@ Generated on: {today_date}
 
 During document generation, you can add custom data that will be merged with the project data:
 
+### Standard Fields (Pre-filled but Fully Editable)
+These fields are pre-filled with common names but can be modified or removed:
+- `zk`, `nr_zk`, `kabel`, `dlugosc`, `data_wykonania`, `st_nr`, `obw`, `wp_short`, `plomba`
+
+### Additional Custom Fields
 - **Custom fields** override project data if they have the same name
 - Use descriptive names like `meeting_notes`, `special_instructions`, `custom_date`
 - Custom fields are available in templates as `{custom_field_name}`
 - Empty custom fields are ignored
+- All fields can be removed if not needed
 
 ### Example Custom Fields:
 - `meeting_notes`: "Please bring project documentation"