Fix Danny Boy, Red River Valley, Parting Glass rhythms

Danny Boy (Londonderry Air): Replace all-quarter encoding with proper
flowing Irish dotted rhythm. Phrases now use dotted-quarter+eighth
pairs (3,1) for melodic motion, half notes (4) on stressed syllables
like "Boy", and dotted-half (6) or whole (8) for held phrase-end
notes like "-ing", "side", "bide". Total duration increases from
~43s/pass to ~50s/pass reflecting the song's true character.

Red River Valley: Slow American ballad now has dotted-quarter+eighth
motion with half-note phrase endings instead of uniform quarter notes.

The Parting Glass: Irish 4/4 ballad now uses proper dotted feel with
stressed syllables held as half/dotted-half notes.

https://claude.ai/code/session_016yrXXcwbdXGoSXkNX8UcP2

index.html

@@ -3555,10 +3555,12 @@ const FOLK_PIECES=(function(){
     3,C4);
 
   // ── Red River Valley ──
+  // Slow American ballad in 4/4. "From this val-ley they say you are go-ing"
+  // Uses dotted-quarter + eighth for the flowing melodic phrases.
   var redriver=folk("Red River Valley","American Traditional (1870s)",85,
     [C4,D4,E4,G4,G4,E4,D4,C4,D4,E4,F4,E4,D4,C4,E4,G4,A4,G4,E4,D4,C4,D4,E4,C4],
     [0,1,2,3,3,2,1,0,1,2,1,2,1,0,2,3,0,3,2,1,0,1,2,0],
-    [2,2,2,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,4],
+    [2,3,1,4,1,3,2,4, 2,3,1,3,1,4,2,4, 2,3,1,3,1,3,1,8],
     4,C4);
 
   // ── Home on the Range ──
@@ -3583,10 +3585,16 @@ const FOLK_PIECES=(function(){
     5,G4);
 
   // ── Danny Boy ──
+  // Londonderry Air: flowing Irish ballad, famous "long-short" dotted feel.
+  // Phrase A: "Oh Dan-ny Boy, the pipes, the pipes are call-ing" (notes 0-10)
+  // Phrase B: "From glen to glen and down the moun-tain side" (notes 11-24)
+  // Phrase C: High passage, peaks at E5 (notes 25-37)
+  // Phrase D: Final resolution back to tonic C (notes 38-48)
+  // Duration units: 1=eighth, 2=quarter, 3=dotted-quarter, 4=half, 6=dotted-half, 8=whole
   var dannyboy=folk("Danny Boy","Irish Traditional (1910s)",72,
     [C4,E4,F4,G4,A4,G4,A4,C5,B4,A4,G4,F4,G4,C4,E4,F4,G4,A4,G4,A4,C5,D5,C5,A4,G4,A4,A4,C5,D5,E5,D5,C5,A4,C5,B4,A4,G4,A4,G4,E4,C4,E4,F4,G4,A4,G4,F4,E4,C4],
     [0,2,1,3,0,3,0,0,3,0,3,1,3,0,2,1,3,0,3,0,0,1,0,0,3,0,0,0,1,2,1,0,0,0,3,0,3,0,3,2,0,2,1,3,0,3,1,2,0],
-    [2,2,2,2,2,2,2,2,2,2,2,2,4,2,2,2,2,2,2,2,2,2,2,2,2,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,4],
+    [2,3,1,4,1,3,1,3,1,3,6, 2,3,1,3,1,4,1,3,1,3,1,3,1,6, 2,1,3,1,4,1,3,1,3,1,3,1,6, 2,3,1,3,1,4,1,3,1,3,8],
     3,C4);
 
   return [ohsusanna,greensleeves,camptown,redriver,homerange,yankee,turkey,dannyboy];
@@ -3783,7 +3791,9 @@ const SINGALONG_PIECES=(function(){
   var parting=pub("The Parting Glass","Irish/Scots (Trad.)",80,
     [E4,G4,A4,B4,A4,G4,E4,D4,E4,G4,A4,B4,D5,B4,A4,G4,E4,G4,A4,B4,A4,G4,E4,D4,E4,G4,A4,B4,D5,B4,A4,G4],
     [2,3,0,3,0,3,2,1,2,3,0,3,1,3,0,3,2,3,0,3,0,3,2,1,2,3,0,3,1,3,0,3],
-    [2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,4],
+    // "Of all the mon-ey that e'er I had / I spent it in good com-pa-ny"
+    // Flowing Irish 4/4 with dotted-quarter+eighth pairs and half-notes on stressed syllables
+    [2,3,1,4,1,3,2,4, 2,3,1,2,6,2,2,6, 2,3,1,4,1,3,2,4, 2,3,1,2,6,2,2,6],
     4,E4);
   var amazing=pub("Amazing Grace","J. Newton (1779)",80,
     [G4,C5,E5,C5,E5,D5,C5,A4,G4,G4,C5,E5,C5,E5,D5,E5,E5,C5,A4,A4,G4,E4,G4,C5,E5,C5,E5,D5,C5],