Make src a package, add collector modules, and allow running src/main.py directly

[MahanKenway]

Motivation

• Fix ModuleNotFoundError: No module named 'src' when running python src/main.py and make the project importable as a package for CI and local execution.
• Provide a structured implementation for collecting, parsing, testing, exporting, and notifying about V2Ray configs to replace the previous single-script approach.
• Improve CI workflow to run the collector as a module and add basic project metadata and developer tooling files.

Description

• Add package layout under src/ with modules for settings (src/config), sources (src/config/sources.py), collection (src/core/collector.py), parsing (src/core/parser.py), testing (src/core/tester.py), exporting (src/core/exporter.py), notifying (src/core/notifier.py), models (src/models), and utilities (src/utils), plus __init__.py files so src is a proper package.
• Implement src/main.py and add a sys.path fallback so python src/main.py works when __package__ is empty, and update scripts/collector.py to prepend the repo root to sys.path and call src.main.main() for direct script invocation.
• Improve robustness of network calls with retrying requests session, safer base64 decoding utilities, structured logging via src/utils/logger.py, and typed dataclasses for Settings and Config objects.
• Update GitHub Actions workflow to install dependencies and run the collector via python -m src.main, add requirements.txt/requirements-dev.txt, pytest.ini, .env.example, .gitignore, license, and contributor docs.
• Add unit tests for parsing and tester logic in tests/test_parser.py and tests/test_tester.py that exercise ConfigParser and ConfigTester behavior.

Testing

• No automated tests were executed in this rollout; test files tests/test_parser.py and tests/test_tester.py were added but pytest was not run.

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Codex Task