Add historical check-in card sharing

app/globals.css

@@ -174,7 +174,7 @@ h1{letter-spacing:-.04em;font-size:clamp(2rem,4vw,2.85rem)}
 .task-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:13px;color:#64748b;font-size:.84rem}.today-button{border:1px solid #bfd3fb;background:#f7faff;color:#1d4ed8;border-radius:999px;padding:7px 11px;font:inherit;font-weight:700;cursor:pointer;transition:.16s background,.16s transform}.today-button:hover{background:#e7f0ff;transform:translateY(-1px)}
 .task:hover{transform:translateX(2px);border-color:#94bafc}.task.done{background:#f2f7ff}
 .task b{background:#e7efff;color:#315fd5}.task.done b{background:#cfe0ff}
-.completion-card{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-top:18px;padding:19px 20px;border:1px solid #bad3ff;border-radius:18px;background:linear-gradient(125deg,#edf5ff,#fff)}.completion-card h3{margin:4px 0 7px;font-size:1.12rem;letter-spacing:-.02em}.completion-card>div>p:last-child{margin:0;color:#64748b;font-size:.88rem;line-height:1.55}.share-card-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;flex:none;border:0;border-radius:12px;background:#2563eb;color:#fff;padding:12px 15px;font:inherit;font-weight:700;cursor:pointer;box-shadow:0 9px 18px #bfdbfe;transition:.16s transform,.16s background}.share-card-button:hover{background:#1d4ed8;transform:translateY(-1px)}
+.completion-card{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-top:18px;padding:21px 22px;border:1px solid #315fd5;border-radius:18px;background:linear-gradient(120deg,#102b63,#2563d8 68%,#4d8cf0);box-shadow:0 14px 28px #bdd6ff}.completion-card .eyebrow{color:#c9ddff}.completion-card h3{margin:4px 0 7px;color:#fff;font-size:1.18rem;letter-spacing:-.02em}.completion-card>div>p:last-child{margin:0;color:#dbeafe;font-size:.9rem;line-height:1.55}.share-card-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;flex:none;border:0;border-radius:12px;background:#fff;color:#1d4ed8;padding:13px 16px;font:inherit;font-weight:800;cursor:pointer;box-shadow:0 9px 18px #102b6355;transition:.16s transform,.16s background}.share-card-button:hover{background:#edf5ff;transform:translateY(-1px)}.history-share-float{position:fixed;right:26px;bottom:24px;z-index:20;display:flex;align-items:center;gap:16px;max-width:calc(100vw - 32px);padding:14px 16px 14px 18px;border:1px solid #315fd5;border-radius:17px;background:linear-gradient(120deg,#102b63,#2563d8);color:#fff;box-shadow:0 18px 38px #102b6377}.history-share-float .eyebrow{margin:0 0 4px;color:#c9ddff}.history-share-float b,.history-share-float span{display:block}.history-share-float b{font-size:.94rem}.history-share-float span{margin-top:3px;color:#dbeafe;font-size:.78rem}
 .review{margin-top:26px}.review textarea{background:#fbfdff;border-color:#d5e0f0}.pill{transition:.15s transform}.pill:hover:not(:disabled){transform:translateY(-1px)}
 aside{display:grid;gap:14px}.side-calendar{margin:0;padding:18px;border-radius:22px;border-color:#d9e6ff;box-shadow:0 16px 36px #bfd5fb77}.calendar-head{gap:10px}.calendar-head h2{font-size:1.22rem;letter-spacing:-.02em}.month-tabs{gap:3px}.month-tabs button{padding:6px 8px;font-size:.76rem;min-width:36px}.weekdays{margin:16px 0 7px;font-size:.7rem;gap:4px}.calendar-grid{gap:4px}.calendar-day{min-height:47px;padding:5px 4px;border-radius:10px;font-size:.8rem}.calendar-day small{font-size:.56rem;line-height:1.1}.calendar-day.chosen{outline-width:2px}.calendar-note{font-size:.7rem;line-height:1.9}.calendar-note i{width:7px;height:7px;margin:0 3px 0 8px}.dark,.side{margin:0;border-radius:20px}.dark{padding:22px;background:linear-gradient(145deg,#102555,#1d4ed8)}.dark h2{font-size:1.45rem;letter-spacing:-.025em}.side{padding:18px;border-color:#d9e6ff;box-shadow:0 10px 25px #dbeafe66}.side p{margin:12px 0;font-size:.8rem}
 @media(max-width:980px){.layout{grid-template-columns:minmax(0,1fr) 300px}.calendar-day{min-height:43px}.calendar-day small{font-size:.51rem}.month-tabs button{padding:5px 6px;min-width:31px}}