- Added extension system support for Python execution events with new event types and handlers.
- Added Python mode theming and execution indicators across all theme files.
- Added `$` and `$$` command prefixes for Python execution in interactive mode.
- Changed Python tool to use cells array instead of single code parameter.
- Renamed workdir parameter to cwd in Bash and Python tools for consistency.
- Added 30+ built-in color themes and comprehensive symbol customization via theme presets and overrides.
- Added status line segment editor with presets, separators, and customizable left/right segments.
- Added Biome CLI-based linter client as alternative to LSP for diagnostics and formatting.
- Added 20MB file size limit for image files to prevent memory issues during serialization.
- Replaced hardcoded Unicode symbols throughout codebase with theme-configurable symbol system.
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