docs: [SDK] Update README for new doc structure

[lenny-goodell]

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• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
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[codecov-commenter]

Codecov Report

Merging #1504 (5912559) into main (095da73) will not change coverage.
The diff coverage is n/a.

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@@           Coverage Diff           @@
##             main    #1504   +/-   ##
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  Coverage   67.40%   67.40%           
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  Files          36       36           
  Lines        3132     3132           
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  Hits         2111     2111           
  Misses        888      888           
  Partials      133      133