refactor(core): complete library rewrite with modern architecture

[vlymar1]

Summary

Complete refactor of the library with modernized client architecture, improved cookie persistence, and comprehensive documentation updates.

Key Changes

Core Architecture

• Refactored VintedClient with clean async context manager pattern
• Modernized HTTP session management with retry logic
• Improved authentication handling with JWT token validation

Storage & Persistence

• Added multiple cookie storage backends: JSON (default), Pickle, Mozilla
• Configurable storage directory and format selection
• Safe defaults with human-readable JSON format

Models & Parsing

• Streamlined dataclass models for CatalogItem and DetailedItem
• Improved field extraction and type safety
• Better error handling for malformed API responses

Documentation

• Complete README rewrite with clear examples
• Added migration guide from v0.x to v1.0
• Comprehensive exception handling documentation
• Updated badges and project metadata

Testing & CI

• Expanded test coverage for all modules
• Updated CI workflows and automation scripts
• Improved Makefile targets for development

Breaking Changes

• Import path: vinted_api_kit → vinted
• Class name: VintedApi → VintedClient
• Proxy format: dict → simple string
• Removed manual locale parameter (auto-detected)

How to Test

Run checks:

make lint-check
make test-coverage

Smoke test:

from vinted import VintedClient

async with VintedClient() as client:
    items = await client.search_items(
        url="https://www.vinted.com/catalog?search_text=test"
    )
    print(f"Found {len(items)} items")

Cookie persistence test:

# First run - saves cookies
async with VintedClient(persist_cookies=True, storage_format="json") as client:
    await client.search_items(url)

# Second run - reuses cookies (faster)
async with VintedClient(persist_cookies=True, storage_format="json") as client:
    await client.search_items(url)

Safety Notes

• Default storage format is json (safe, portable)
• pickle format available but documented as unsafe for untrusted data
• No breaking changes for common usage patterns

Post-Merge Actions

• Bump version in pyproject.toml to 1.0.0
• Update CHANGELOG.md with release notes
• Test build: hatch build
• Publish to TestPyPI for validation
• Publish to PyPI and create GitHub release tag