Updated extension branding to the new Posttely logo.

• New toolbar icon (red P mark)
• Popup and settings now use the bundled horizontal Posttely logo
• Fixes stale cached logo from the website

Updated extension icon to match the current Posttely branding.

This release replaces the previous icon with the new red Posttely mark. No feature, permission, or behavior changes in this update.

Version 1.2.0
- Refreshed branding: the extension now matches Posttely's updated brand color.
- Brand/accent color is applied dynamically from your Posttely account, so the extension stays in sync with the web app.
- Added support for the www.posttely.com domain.
- Minor styling polish across the popup and options pages.

Version 1.1.0

• Fixed: Extension now correctly connects to posttely.com (previous version had a configuration issue in background processes)
• New: Character limit now adjusts per platform — LinkedIn (3,000), Threads (500), X/Twitter (280), etc.
• New: Using "Share to Posttely" from right-click context menu now pre-fills the compose box automatically
• New: Version number in Settings → About is now always accurate and dynamic
• Improved: Schedule form now validates that the chosen time is in the future
• Improved: UI polish across the popup and settings page
• Fixed: "Connect channels" link now points to the correct dashboard URL
• Security: Replaced all innerHTML assignments with safe DOMParser-based rendering