Merge branch 'master' of https://github.com/amirlehmam/wmux

docs: rewrite README to match cmux quality and structure

HTML feature table, centered hero header with badges, screenshot,
personal "Why wmux?" narrative, shell integration section, full
keyboard shortcut tables, CLI reference, socket API docs, session
restore, config, and architecture overview. Same tone as cmux.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

fix: PowerShell execution policy bypass + proper ICO icon

- Add -ExecutionPolicy Bypass to PowerShell spawn args so shell
  integration script loads without requiring code signing
- Rebuild icon.ico with all 7 sizes (16-256px) using PNG compression
  for proper Windows taskbar/explorer display

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>