Free Memory Widget (#155)

* FreeMemory widget:

  Description: Shows system memory usage (used/total) in a compact format like Mem: 12.4G/16.0G

  Features:
  - On macOS: Uses vm_stat to calculate memory like htop (Active + Wired pages)
  - On other platforms: Falls back to Node.js os.freemem()/os.totalmem()
  - Smart byte formatting (G, M, K, B)
  - Supports raw value mode (omits "Mem:" prefix)
  - Default color: cyan

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* Version bump and README update

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Matthew Breedlove <sirmalloc@gmail.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ccstatusline",
-  "version": "2.0.28",
+  "version": "2.0.29",
   "description": "A customizable status line formatter for Claude Code CLI",
   "module": "src/ccstatusline.ts",
   "type": "module",