feat: achieve 100% test coverage and zero quality issues

[alexx-ftw]

Resolves #61

Summary

This PR achieves 100% test coverage and establishes a zero-defect quality baseline for the ChatMock repository by adding comprehensive test suites, fixing all lint errors, and resolving all type checking issues.

Key Achievements

✅ 100% Code Coverage - All 2056 statements and 858 branches covered
✅ Zero Lint Errors - All Ruff checks passing
✅ Zero Type Errors - All mypy type checks passing
✅ 425 Passing Tests - Comprehensive test suite with no failures
✅ Pre-commit Hooks - Automated quality gates configured

Changes Overview

Test Coverage Additions

• Added comprehensive coverage for all core modules including cli.py, limits.py, utils.py, routes_openai.py, routes_ollama.py, oauth.py, session.py, transform.py, upstream.py, and reasoning.py
• Comprehensive edge case coverage for error paths, HTTP failures, and input validation
• Added test helpers and fixtures for consistent test setup

Code Quality Fixes

Type Safety (mypy):

• Fixed variable redefinition in reasoning.py
• Fixed list item type errors in cli.py
• Added targeted type: ignore comments for false positives
• Added mypy configuration with per-module overrides
• All 73 type errors resolved

Lint Fixes (ruff):

• All code style issues resolved
• Import sorting corrected
• Line length issues fixed

Configuration Improvements

• Added pyproject.toml with comprehensive tool configurations
• Pre-commit hooks configured with automated quality checks
• Coverage configured with 100% requirement and branch coverage

Commit History

✨ Single clean commit - All changes squashed into one comprehensive commit for maintainable history

Test Plan

• ✅ All 425 tests passing
• ✅ 100% coverage verified: pytest --cov=chatmock --cov-report=term-missing
• ✅ No lint errors: ruff check .
• ✅ No type errors: mypy chatmock
• ✅ Pre-commit hooks passing

Breaking Changes

None - all changes are additive (tests) or non-functional (type hints, lint fixes)

Dependencies

No new runtime dependencies added - only test and development dependencies

Related

• Resolves: Achieve 100% test coverage and zero quality issues baseline #61

[alexx-ftw]

📋 Tracking Issue: #61

This PR implements the complete quality baseline initiative described in issue #61, achieving all defined success criteria:

• ✅ 100% test coverage across all modules
• ✅ Zero lint errors (ruff)
• ✅ Zero type errors (mypy)
• ✅ Comprehensive test suite (425 tests)
• ✅ Automated quality gates (pre-commit hooks)

The implementation is complete and ready for review. Merging this PR will close #61.

[RayBytes]

For tests, it's obviously said that you should have enough to encompass all your features. However, this is an excessive amount of tests, 425??
Can we not tone this down to only the clear cut features of the project, instead of testing things like if usage limits print, or if stuff is able to convert data properly? whenever features change, all these tests will also need to be changed too... please significantly decrease the amount of tests to a reasonable amount, which encompass ollama, openai endpoints, with reasonable tests, and ensure the config works ok.