Add pytheory play Cmaj7 example with output

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

data/essays/2026-03-22-pytheory_breaking_through_five_years_of_creative_block_with_ai.md

@@ -270,6 +270,12 @@ Because sometimes you just want a quick answer without writing a script:
 # Play a C major chord
 $ pytheory play C4 E4 G4
 
+# Play a chord by name
+$ pytheory play Cmaj7
+  Playing: C major 7th (C4 E4 G4 B4)
+  Synth:   sine
+  Duration: 1000 ms
+
 # What's in the key of D major?
 $ pytheory key D major