kb: add bossa nova guitar pack

5 progressions (Ipanema A-section, minor ii-V-i with m6 tonic, Blue
Bossa 16-bar, One Note Samba chromatic chain, Corcovado descent) x 2
plays on alternating root-string sets. Joao Gilberto rhythm layers
documented (thumb surdo + syncopated block, two-bar tied pattern,
partido alto contrast), improv map, sourced Ipanema melodic cell.
Validator caught 6 quality mismatches (6/9 grips on maj7/min7 steps)
- content fixed, gate untouched. Validator and build green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/data/kb/index.js

@@ -9,6 +9,9 @@ import bluesGuitar from './blues/guitar.js'
 import rockMeta from './rock/meta.js'
 import rockProgressions from './rock/progressions.js'
 import rockGuitar from './rock/guitar.js'
+import bossaMeta from './bossa/meta.js'
+import bossaProgressions from './bossa/progressions.js'
+import bossaGuitar from './bossa/guitar.js'
 
 export default {
   jazz: {
@@ -26,4 +29,9 @@ export default {
     progressions: rockProgressions,
     instruments: { guitar: rockGuitar },
   },
+  bossa: {
+    meta: bossaMeta,
+    progressions: bossaProgressions,
+    instruments: { guitar: bossaGuitar },
+  },
 }