Fix help manual layout: shrink tabs to fit panel, space implant rows

- 10+ tabs at fixed 108px overflowed the 920px panel; tabs now shrink to fit
- Implant rows grew a rarity/cap sub-line but kept 20px spacing; now 26px
  with 10 rows per column (20 items/page, 5 pages for 82 items)
- Bump asset cache to v=39; smoke test asserts tabs stay on-screen

js/sfxbank.js

@@ -115,7 +115,7 @@ const SfxBank = {
     if (this.buffers.has(name) || this.pending.has(name) || this.failed.has(name)) return;
     const file = this.FILES[name];
     if (!file || !this.ctx || typeof fetch !== 'function') return;
-    const job = fetch('/assets/sfx/' + encodeURIComponent(file) + '?v=38')
+    const job = fetch('/assets/sfx/' + encodeURIComponent(file) + '?v=39')
       .then(r => { if (!r.ok) throw new Error('HTTP ' + r.status); return r.arrayBuffer(); })
       .then(bytes => this.ctx.decodeAudioData(bytes))
       .then(buffer => this.buffers.set(name, this.trim(buffer)))