feat(core): Python language support

[prosdev]

Summary

dev-agent now indexes Python codebases. All MCP tools work with Python automatically.

What it does

PythonScanner extracts from .py files:

• Functions (sync + async), classes, methods
• Decorators (@app.route, @pytest.fixture, @property)
• Type hints in signatures (def foo(x: int) -> str)
• Docstrings (triple-quote, first expression in body)
• __all__ for export control, _ prefix convention as fallback
• Callees from function bodies (recursive descent)
• Code snippets for search result previews
• Imports (import, from...import, relative imports)

Pattern rules for dev_patterns on Python files:

• Error handling: try/except, raise, except clauses
• Import style: import, from-import, relative imports
• Type coverage: typed parameters, return types, function count

Infrastructure improvements:

• isTestFile() refactored to language-aware pattern map
• QUERIES_BY_LANGUAGE map replaces if/else chain
• Skip generated files (_pb2.py, migrations, # Generated by)

Changes

File	What
packages/core/src/scanner/python.ts	PythonScanner (~520 lines)
packages/core/src/scanner/python-queries.ts	8 S-expression extraction queries
packages/core/src/scanner/index.ts	Register PythonScanner
packages/core/src/utils/test-utils.ts	Refactored to language-aware patterns
packages/core/src/pattern-matcher/rules.ts	9 Python pattern rules
packages/core/src/pattern-matcher/wasm-matcher.ts	Add Python to language map + supported set
packages/core/src/services/pattern-analysis-service.ts	QUERIES_BY_LANGUAGE map
packages/core/src/scanner/tree-sitter.ts	Add 'python' to TreeSitterLanguage
packages/dev-agent/scripts/copy-wasm.js	Bundle tree-sitter-python.wasm (476KB)

Test plan

• 22 Python scanner tests (functions, classes, methods, imports, async, docstrings, all, callees, snippets, exports, parity)
• 5 isTestFile Python tests (test_*.py, *_test.py, conftest.py, JS/TS compat)
• 1673 total tests pass (up from 1651)
• Build + typecheck pass

Supported languages

Language	Scanner	Features
TypeScript/JavaScript	ts-morph	Functions, classes, interfaces, types, arrow functions, hooks
Python	tree-sitter	Functions, classes, methods, decorators, type hints, docstrings
Go	tree-sitter	Functions, methods, structs, interfaces, generics
Markdown	remark	Documentation sections

Generated with Claude Code