refactor(formatter): isolate protected text helpers

[MayerTim]

Summary

• Add shared formatter scanner helpers for protected-text outside lookups and outside-segment rewrites.
• Replace duplicated outside-lookup construction in query clause, inline IF, and parenthesis formatting.
• Replace local outside-segment rewrite loops in keyword casing and Watcom statement-continuation cleanup.
• Preserve the existing scanner state model and formatter behavior.

Validation

• npm run validate
• npm run package:vsix

Notes

This PR is behavior-preserving. It does not change formatter output, formatter pass order, formatter defaults, metadata behavior, diagnostics behavior, extension behavior, packaging behavior, or public documentation.