Add release notes for Cache Status extension

Created comprehensive release notes tracking version
history from 0.0.1 to 0.0.8, detailing features,
fixes, and improvements for each iteration of the
browser extension.

Author: bartTC

RELEASE_NOTES.md

@@ -0,0 +1,68 @@
+# Release Notes
+
+What's new in each version of Cache Status.
+
+---
+
+## Version 0.0.8
+
+- Fixed: `x-cache-status` header now displayed (used by nginx and other servers)
+- Added: `x-cache-date` header support
+- Renamed app from "CF Cache Status" to "Cache Status"
+
+---
+
+## Version 0.0.7
+
+- Popup updates live as headers and performance metrics arrive
+- "No Data" message now explains to navigate or reload
+
+---
+
+## Version 0.0.6
+
+- Redesigned popup with hero section showing status at a glance
+- Performance metrics displayed in a grid layout
+- Improved dark mode colors
+
+---
+
+## Version 0.0.5
+
+- Fixed CDN detection not working in some cases
+- New app icon
+
+---
+
+## Version 0.0.4
+
+- Added edge location display (e.g., "Frankfurt, DE" from FRA56)
+- Improved Akamai detection via `server` header
+- Fixed URL showing redirect URL instead of final page URL
+
+---
+
+## Version 0.0.3
+
+- Fixed app icon not showing in Safari extension preferences
+
+---
+
+## Version 0.0.2
+
+- Added performance metrics: TTFB, DNS, TCP, TLS, download time, transfer size
+- Added CloudFront Origin Shield explanation on MISS
+- Added Fastly tiered cache diagram showing X-Cache layer breakdown
+- Headers now displayed in Title-Case
+
+---
+
+## Version 0.0.1
+
+Initial release.
+
+- Toolbar badge showing cache status (HIT/MISS/EXPIRED/BYPASS/DYNAMIC)
+- Popup with cache headers and response metadata
+- Edge location mapping (IATA codes → city names)
+- Multi-CDN support: Cloudflare, CloudFront, Fastly, Akamai, Bunny CDN, Varnish
+- Dark mode support