Add detailed skip tracking for phone imports

- Track skipped_no_phone and skipped_no_id separately
- Display skip information in admin UI with warning icon
- Clarify that empty phone numbers cannot be imported (PK constraint)
- Update documentation to explain expected skip behavior
- Example: 143 rows without phone numbers is correct, not an error

When importing PHONE.csv with empty phone numbers:
- Rows are properly skipped (cannot have NULL in primary key)
- User sees: '⚠️ Skipped: 143 rows without phone number'
- This is expected behavior, not a bug

docs/PHONE_IMPORT_FIX.md

@@ -55,9 +55,23 @@ The function now returns detailed statistics:
 - `inserted`: New records added
 - `updated`: Existing records updated
 - `skipped`: Duplicate combinations within the CSV
+- `skipped_no_phone`: Rows without a phone number (cannot import - phone is part of primary key)
+- `skipped_no_id`: Rows without an ID (cannot import - required field)
 - `errors`: List of error messages for failed rows
 - `total_rows`: Total rows in CSV
 
+### Understanding Skipped Rows
+**Important**: The `phone` field is part of the composite primary key `(id, phone)`. This means:
+- You **cannot** import a phone record without a phone number
+- Empty phone numbers will be skipped (this is expected and correct behavior)
+- The web UI will display: `⚠️ Skipped: X rows without phone number`
+
+**Example**: If your CSV has 26,437 rows and 143 have empty phone numbers:
+- Total rows: 26,437
+- Success: 26,294 
+- Skipped (no phone): 143
+- **This is working correctly** - those 143 rows don't have phone numbers to import
+
 ## Testing
 After deploying this fix:
 1. Uploading `PHONE.csv` for the first time will insert all records