v0.8.0

Built-in Function Catalog — Hover, SignatureHelp & Localized Completion

Added

• Built-in function catalog — all 48 GPPL built-in functions (28 numeric, 16 string, 4 logical) described in a structured JSON catalog with per-locale text overlays (EN/RU/DE)
• Hover for built-in functions — full signature, category, localized description, and usage examples
• Signature Help for built-in functions — parameter hints with active parameter highlighting (previously only for @-procedures)
• Localized completion documentation — built-in functions show localized summary in completion popup

Changed

• Completion handler migrated from 6 hardcoded arrays to single catalog loop — adding a new function requires only a JSON entry
• SignatureHelp handler refactored to support both @-procedures and built-in functions

Stats

• 27 new tests (133 total, all passing)
• Server binary: self-contained .NET 8 win-x64