Add feature set import export

public/styles.css

@@ -18,3 +18,5 @@ button,input,textarea{font:inherit} button{cursor:pointer} a{color:inherit;text-
 @media(max-width:1050px){.app-shell{grid-template-columns:1fr}.sidebar{display:none}.workspace{padding:14px}.topbar{grid-template-columns:auto 1fr}.profile-card,.progress-card{grid-column:1/-1}.sorting-layout{grid-template-columns:1fr}.capture-strip form{grid-template-columns:1fr 1fr}.capture-strip button{grid-column:1/-1}.utility-row{grid-template-columns:1fr}.utility-row button{border-right:0;border-bottom:1px solid var(--border)}.utility-row button:last-child{border-bottom:0}}
 .shortcut-hint{margin:10px 2px 0;color:var(--slate-600);font-size:12px}.shortcut-hint kbd{display:inline-grid;place-items:center;min-width:22px;height:20px;padding:0 5px;border:1px solid var(--border);border-bottom-width:2px;border-radius:4px;background:#fff;color:var(--navy-950);font-weight:800}.timeline-line.drag-over{outline:2px dashed var(--blue-600);outline-offset:8px;background:linear-gradient(90deg,rgba(22,163,74,.06),rgba(37,99,235,.06),rgba(245,158,11,.06),rgba(124,58,237,.06))}.node[draggable="true"]{cursor:grab}.node[draggable="true"]:active{cursor:grabbing}.toast{display:flex;align-items:center;gap:12px}.toast button{border:1px solid rgba(255,255,255,.35);background:rgba(255,255,255,.12);color:#fff;border-radius:4px;padding:6px 9px;font-weight:800}.detail label input[name="labels"]{width:100%;border:1px solid var(--border);border-radius:6px;padding:11px 12px;background:#F8FAFC;color:var(--slate-900);margin-top:6px}.profile-menu button.selected{background:#F0E9FF;color:var(--purple-600);font-weight:900}
 @media(max-width:680px){.workspace{padding:10px}.topbar{padding:12px;gap:12px}.project-title h1{font-size:21px}.sorting-grid{grid-template-columns:1fr 1fr;gap:9px}.zone{min-height:142px;padding:12px}.zone-icon{font-size:30px}.zone strong{font-size:14px}.zone span{font-size:12px}.capture-strip form,.deck-actions,.detail-grid,.detail-actions{grid-template-columns:1fr}.timeline{overflow-x:auto}.timeline-line{min-width:760px}.feature-card{min-height:160px}.feature-card::before,.feature-card::after{display:none}}
+
+.feature-set-panel{display:grid;grid-template-columns:minmax(280px,.9fr) minmax(420px,1.4fr);gap:16px;background:linear-gradient(135deg,rgba(6,27,51,.96),rgba(9,38,75,.92));color:white;border:1px solid rgba(255,255,255,.12);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px;margin-bottom:18px;overflow:hidden;position:relative}.feature-set-panel::before{content:"";position:absolute;inset:auto -80px -120px auto;width:260px;height:260px;background:radial-gradient(circle,rgba(69,184,255,.25),transparent 65%);pointer-events:none}.feature-set-copy{position:relative;z-index:1}.feature-set-copy .section-label{color:#A7D8FF}.feature-set-copy h2{margin:7px 0 8px;font-size:22px;letter-spacing:-.03em}.feature-set-copy p{margin:0;color:#D9E8FF;line-height:1.5;font-size:13px}.feature-set-copy code{background:rgba(255,255,255,.10);border:1px solid rgba(255,255,255,.10);border-radius:4px;padding:1px 5px;color:#fff}.feature-set-actions{position:relative;z-index:1;display:grid;gap:10px}.feature-set-actions textarea{width:100%;min-height:178px;resize:vertical;border:1px solid rgba(255,255,255,.16);border-radius:6px;background:rgba(2,8,23,.64);color:#EAF6FF;padding:12px;font-family:"JetBrains Mono","SFMono-Regular",ui-monospace,monospace;font-size:12px;line-height:1.45;outline:none}.feature-set-actions textarea:focus{border-color:#45B8FF;box-shadow:0 0 0 3px rgba(69,184,255,.16)}.feature-set-toolbar{display:flex;gap:10px;flex-wrap:wrap;align-items:center}.feature-set-toolbar button,.file-pick{border:1px solid rgba(255,255,255,.20);border-radius:6px;background:rgba(255,255,255,.10);color:white;padding:10px 12px;font-weight:850;box-shadow:0 10px 24px rgba(0,0,0,.12)}.feature-set-toolbar button:hover,.file-pick:hover{background:rgba(255,255,255,.16)}.file-pick input{position:absolute;inline-size:1px;block-size:1px;opacity:0;pointer-events:none}@media(max-width:1050px){.feature-set-panel{grid-template-columns:1fr}.feature-set-actions textarea{min-height:220px}}