feat: make SqlFormatter private and add context-aware indentation

- Make SqlFormatter private property on DeparserContext
- Add public methods: indent(), newline(), parens(), format(), isPretty()
- Replace all context.formatter.* references with direct context methods
- Fix CREATE TABLE constraint indentation using context.indentLevel
- UNIQUE and FOREIGN KEY constraints now properly indented relative to table structure
- Context spawning with increased indent levels for table elements
- All 279 test suites continue to pass

Co-Authored-By: Dan Lynch <[email protected]>

Author: devin-ai-integration[bot]