Fix code quality: resolve 209 linting errors, add type hints, fix YAML/template bugs

[Copilot]

Codebase audit requested ("看看有撒能优化的没" - "see what can be optimized"). Found and fixed linting violations, missing type annotations, and two bugs.

Changes

Code Quality (209 issues)

• Updated pyproject.toml to modern ruff lint configuration format
• Fixed import sorting violations across all modules
• Removed trailing whitespace (W293 errors)
• Split long lines exceeding 100 chars

Type Safety (29+ functions)

• Added return type annotations to all functions
• Added proper imports (Union, Generator, Optional)

# Before
def print_success(message: str):
    """Print success message"""

# After  
def print_success(message: str) -> None:
    """Print success message"""

Bug Fixes

• YAML indentation: Fixed logging.file key in default config template (was indented 4 spaces instead of 2)
• Template validation: Fixed inconsistency between required_templates list (referenced teaching-prompt-template.md) and allowed_templates set (didn't include it)

# Before: Lists were inconsistent
allowed_templates = {"outline-template.md", "progress-template.md", ...}
required_templates = ["outline-template.md", "teaching-prompt-template.md", ...]

# After: Aligned to same set
required_templates = ["outline-template.md", "progress-template.md", ...]

Security

CodeQL scan: 0 alerts

Original prompt

看看有撒能优化的没

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