Add FXMacroData release-calendar integration

[roberttidball]

Summary

• add a read-only FXMacroData integration for official-source macro release-calendar data
• use the public https://fxmacrodata.com/api/v1/calendar/{currency} endpoint with optional FXMACRODATA_API_KEY
• support event-risk workflows by exposing release names, dates, timestamps, market tiers, and source metadata

Validation

• git diff --check
• Python helpers: python -m py_compile on changed .py files where applicable
• TypeScript repos: native build/type checks where applicable
• Live smoke: FXMacroData USD calendar helper returned a locally limited set of public top-tier rows

Note: R is not installed in this local environment, so R package changes were reviewed but not executed with R CMD check.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.24%. Comparing base (496c3e4) to head (e0f2e37).
⚠️ Report is 22 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #521      +/-   ##
==========================================
+ Coverage   65.58%   73.24%   +7.65%     
==========================================
  Files          94      109      +15     
  Lines        1537     1719     +182     
  Branches      181      260      +79     
==========================================
+ Hits         1008     1259     +251     
+ Misses        517      448      -69     
  Partials       12       12              

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