kb: add pop guitar pack (task P-02)

5 pop progressions x 2 plays: axis (I-V-vi-IV), '50s doo-wop, Canon pop line,
Mixolydian bVII, minor loop (i-bVI-bIII-bVII). Open campfire + movable/barre play each;
sus taught as fills (chords voiced plain). KB now 10 styles / 50 progressions / 100 plays.
Critic PASS (voicings hand-verified, no duplicate ids).

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

src/data/kb/pop/meta.js

@@ -0,0 +1,7 @@
+export default {
+  id: 'pop',
+  label: 'Pop',
+  feel: 'straight',
+  tempoRange: [70, 132],
+  character: 'A handful of diatonic chords looped without apology — the four-chord "axis", the doo-wop turn, the Canon line — where the arrangement and the hook, not the harmony, carry the song.',
+}