Add --force_curly_braces option to insert braces around single-statem…

[burner]

…ent bodies.

When enabled, the preprocessor inserts synthetic { and } tokens around braceless bodies for all block header constructs: if, else, for, foreach, while, do, scope, synchronized, with, catch, debug, version, finally, and their combinations (static if, static foreach, etc.). Implementation uses token stream preprocessing so the formatter's existing brace-handling logic handles style and indentation naturally. Synthetic tokens use size_t.max-based indices to avoid collisions with AST info lookups. Handles compound constructs correctly:

• try/catch/finally chains as single statements
• Nested braceless blocks (each level gets its own braces)
• Mixed braced/braceless siblings (only braceless branches get braces)
• else if/else version/else static if chains (no double-wrapping)
• debug/version with and without parens
• Respects // dfmt off / // dfmt on regions