Fixes Firefox setup displaying Chrome settings and instructions. Firefox now shows its own add-on permissions guidance and allows choosing or dropping a Markdown file without automatic file access. Reader permission recovery and popup guidance are corrected in English, Spanish and Portuguese. Chrome, Edge and Brave retain their native configuration routes through the same shared codebase. No new permissions.

Version 0.1.5 unifies the Chrome and Firefox extension on one shared codebase and release version.

• Improved local Markdown file opening and reading preferences.
• Added Mermaid diagrams with zoom, pan and source-copy controls.
• Isolated diagram rendering and strengthened handling of untrusted content and external resources.
• Fixed keyboard focus restoration when switching reader panels and closing them with Escape.