Release v1.20.1

[GaspardKirira]

v1.20.1 — Improved CLI Error UX & Build Feedback

✨ CLI — Error reporting & diagnostics

• Introduce Python-like compiler error rendering with code frames
  (file:line:column + surrounding context)
• Highlight only the faulty line with a red caret (^) for instant readability
• Safely truncate very long lines with UTF-8–aware ellipsis
• Add precise, Vix-style hints for common mistakes
  (e.g. Response::json() misuse)
• Hide verbose alternative diagnostics unless log level is debug or trace
• Improve run / script error reporting for clearer, actionable diagnostics

🔨 CLI — Build output & Ninja integration

• Restore live Ninja progress output ([x/y %]) during builds
• Filter noisy compiler command output in live mode
• Keep full raw build logs in build.log for post-mortem diagnostics
• Let ErrorHandler display structured, human-readable errors on failure
• Introduce progress-only build output mode
• Fix unused variables and header warnings in build pipeline

🧩 Internal

• Minor internal cleanups to support improved error UX
• No breaking changes