NonBlockingRTTTL 1.3.0 regression fixture

Source: https://github.com/end2endzone/NonBlockingRTTTL/tree/1.3.0
The official 1.3.0 tag's source is vendored as ASCII JSON for offline tests.
Decode the "source" field in src/NonBlockingRtttl.cpp.json to recover the
exact reviewed upstream CPP. The header is unchanged. LICENSE and AUTHORS
retain the original MIT attribution.
No firmware code is linked from this directory.

Canonical normalization is LF line endings and ASCII-only text. The upstream
tag already has both, so no bytes or executable statements are changed.

Unpatched CPP SHA256:
b50c159c8806d177398972bf8f94ca762532a855b60cb1d3aa9c3ebf021423ca
Patched private CPP SHA256:
29204341d99b8adeef501c0d4cb47a4137534ebe6a30f2e6b3032d558aeef802
Unchanged header SHA256:
abea0a4870e58222fdefd1e88d291136518912e83880af30d1c85d39d7bd5cc1
LICENSE SHA256:
44bbc2541c595d5d8790f9b0be9a56fc88c9a500ab6bd2a88b4e00f8e28f0585
Original AUTHORS SHA256 (trailing whitespace trimmed in copy):
35b555001d2fd35c64002cb517bd1abce2d502b88540aff61d6ae5387b697c45
