Josh preset: declipped and level-normalized reference

The exported clip opened ~10 dB hotter than the rest with clipped peaks,
which carried into renders. Reference is now adeclip + dynaudnorm +
loudnorm (-23 LUFS, -2 dBTP peak), preview clip regenerated. Backend
redeployed (v23) with the new WAV.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017bjX8vNkBk9Rjt2SToVF75

public/voices/Josh.m4a

@@ -1,3 +1,3 @@
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-size 148781
+oid sha256:79a76ddcca6461b23233e25803159e884138f9af5dd02b7c449db1c135bc9d9b
+size 149210