docs: Add "Exchange Rate Converter" extensions to homepage

[jy00566722]

Add two plugins developed using wxt: Exchange Rate Converter (one Chinese version, one international version)

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.08%. Comparing base (a19f9e1) to head (f521f8e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #808      +/-   ##
==========================================
+ Coverage   87.01%   87.08%   +0.06%     
==========================================
  Files         120      120              
  Lines       10095    10095              
  Branches      992      994       +2     
==========================================
+ Hits         8784     8791       +7     
+ Misses       1296     1289       -7     
  Partials       15       15              

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