kb: add gospel guitar pack (task P-01)

5 gospel progressions x 2 plays: cascading 2-5-1s, 6-2-5-1 + plagal Amen, IV-#iv°7-I
passing dim, modern sus/9th praise vamp, iii-vi back-door. Shell/sus/9th voicings, all
pitch-class-verified. Registered in kb/index.js. Validator: 9 styles / 45 progressions /
90 plays. Critic PASS.

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

src/data/kb/index.js

@@ -24,6 +24,9 @@ import countryGuitar from './country/guitar.js'
 import rnbMeta from './rnb/meta.js'
 import rnbProgressions from './rnb/progressions.js'
 import rnbGuitar from './rnb/guitar.js'
+import gospelMeta from './gospel/meta.js'
+import gospelProgressions from './gospel/progressions.js'
+import gospelGuitar from './gospel/guitar.js'
 
 export default {
   jazz: {
@@ -66,4 +69,9 @@ export default {
     progressions: rnbProgressions,
     instruments: { guitar: rnbGuitar },
   },
+  gospel: {
+    meta: gospelMeta,
+    progressions: gospelProgressions,
+    instruments: { guitar: gospelGuitar },
+  },
 }