feat: refine archived habit management

frontend/src/style.css

@@ -65,7 +65,8 @@ main{background:var(--surface-base)}
 .soft-button,.danger-button,.file-button,.secondary,.restore,.archived-toggle,.archived-countdowns button{background:var(--surface-raised);border-color:var(--border-cream);box-shadow:var(--highlight-inner)}
 .primary,.primary-small,.unified-fab{background:var(--accent);color:#fff}
 .danger-button{color:var(--danger);border-color:#dba99d;background:#fff8f5}.inline-error,.purge-list-error{color:var(--danger);background:#fff0ec}.task-check[aria-pressed="true"] .task-check-mark,.habit-row.done .habit-check .task-check-mark{background:var(--success);border-color:var(--success)}
-@media(max-width:930px){.habit-archive-toggle{width:100%;min-height:44px;appearance:none;background:var(--surface-raised);border:1px solid var(--border-cream);box-shadow:none;justify-content:flex-start}.archived-habits{width:100%;display:grid;gap:0}.archived-habits>button{width:100%;min-height:44px;appearance:none;display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:12px;padding:10px 12px;color:inherit;text-align:left;background:var(--surface-raised);border:0;border-bottom:1px solid var(--border-cream);border-radius:0;font:inherit}.archived-habits>button span{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.archived-habits>button small{color:var(--muted);white-space:nowrap}}
+.habit-archive-section{display:grid;gap:0}.habit-archive-toggle{width:100%;min-height:44px;display:grid;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;text-align:left}.habit-archive-toggle>span{min-width:0}.habit-archive-toggle>svg:last-child{transition:transform .16s ease}.habit-archive-toggle>svg.expanded{transform:rotate(90deg)}.archived-habits{width:100%;display:grid;gap:0;background:var(--surface-raised);border:1px solid var(--border-cream);border-radius:var(--radius-card);overflow:hidden}.archived-habit-row{width:100%;min-height:44px;appearance:none;display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:12px;padding:10px 12px;color:inherit;text-align:left;background:var(--surface-raised);border:0;border-bottom:1px solid var(--border-cream);font:inherit}.archived-habit-row:last-child{border-bottom:0}.archived-habit-row>span{min-width:0;display:grid;gap:3px}.archived-habit-row b,.archived-habit-row small{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.archived-habit-row small{color:var(--muted);font-size:11px}.archived-habit-row>svg{flex:none}.habit-archive-status{min-height:44px;margin:0;padding:12px;display:flex;align-items:center;justify-content:space-between;gap:12px}.app-sheet__danger{display:flex;gap:8px}.app-sheet__danger>button{min-height:44px}.habit-restore-button{flex:1}.habit-delete-button{flex:1}
+@media(max-width:930px){.habit-archive-section{width:100%;gap:0}.habit-archive-toggle{width:100%;min-height:44px;appearance:none;background:var(--surface-raised);border:1px solid var(--border-cream);box-shadow:none}.archived-habits{width:100%;display:grid;gap:0}.archived-habit-row{width:100%;min-height:44px;appearance:none;grid-template-columns:minmax(0,1fr) auto;background:var(--surface-raised);border-bottom:1px solid var(--border-cream)}.habit-detail-sheet.app-sheet--detail{width:100%;border-radius:var(--sheet-radius) var(--sheet-radius) 0 0!important}}
 input,select,textarea,.search{background:var(--surface-raised);border-color:var(--border-cream);border-radius:var(--radius-control);box-shadow:var(--highlight-inner)}
 .search input,.detail-title textarea{background:transparent;box-shadow:none}
 .sidebar-popover button,.sidebar-action-sheet .app-sheet__body button,.app-sheet--actions .app-sheet__body>button,.more-sheet>button{background:var(--surface-raised)}