docs: Move initial documentation to docs/ directory and update with implementation status

- Move pathao_srs.md to docs/srs.md with complete implementation status
- Move pathao_api_docs.md to docs/api_reference.md with current API details
- Move pathao_dev_guide.md to docs/development_guide.md with architecture overview
- Move pathao_implementation_checklist.md to docs/implementation_checklist.md
- Update all documents to reflect completed implementation (v0.1.0)
- Mark Phase 16 (Final QA) as complete with 97% test coverage
- Remove original files from root directory for cleaner structure
- All requirements from SRS have been successfully implemented and verified

Author: mojnomiya

pathao_api_docs.md docs/api_reference.mdpathao_api_docs.md renamed to docs/api_reference.md

@@ -1,7 +1,8 @@
-# Pathao Python SDK - API Documentation
+# Pathao Python SDK - API Reference
 
-**Version:** 1.0.0  
-**Last Updated:** January 2026
+**Version:** 0.1.0  
+**Last Updated:** January 2026  
+**Status:** Complete Implementation ✅
 
 ---
 
@@ -27,16 +28,17 @@
 
 The Pathao Python SDK provides a clean, Pythonic interface to the Pathao Courier Merchant API. It handles authentication, request/response serialization, error handling, and provides convenient methods for all supported operations.
 
-### Features
+### Features ✅
 
 - ✅ OAuth 2.0 authentication with automatic token refresh
 - ✅ Type hints throughout the codebase
 - ✅ Comprehensive input validation
-- ✅ Detailed error messages
+- ✅ Detailed error messages with custom exception hierarchy
 - ✅ Support for both Sandbox and Production environments
 - ✅ Batch operations support
-- ✅ Async-friendly design
-- ✅ Extensive documentation and examples
+- ✅ Exponential backoff retry logic
+- ✅ Secure logging with sensitive data masking
+- ✅ 97% test coverage with 196 unit tests
 
 ---
 
@@ -400,7 +402,7 @@ Create multiple orders in a single request.
 
 | Parameter | Type | Required | Description |
 |-----------|------|----------|-------------|
-| `orders` | List[Dict] | Yes | List of order dictionaries (see create_single for fields) |
+| `orders` | List[Dict] | Yes | List of order dictionaries (see create for fields) |
 
 **Returns:** `BulkOrderResponse` object
 
@@ -1013,4 +1015,6 @@ except PathaoException as e:
 
 ---
 
-**Documentation End**
+**Documentation Status:** ✅ Complete - Reflects current implementation  
+**Last Updated:** January 2026  
+**SDK Version:** 0.1.0