feat: combine session actions into options dropdown

SessionCard desktop view:
- Retain primary action button: Open (active) or Start (inactive)
- Replace individual Stop/Tunnel/Delete buttons with a single Options
  dropdown triggered by a ⋯ button
- Dropdown contains applicable actions:
  - Active: Stop, Recreate Tunnel (web), Delete
  - Inactive: Start, Delete
- Add window.confirm before Delete as a safety net
- Dropdown closes on outside click or Escape key
- Add 'more' icon (DotsThreeVertical) to icon component
- Add session-options-dropdown CSS with subtle animation

Mobile view unchanged (already uses MobileActionSheet).

Quality gates: tsc --noEmit pass, npm run build pass, 82/82 tests pass

apps/web/src/styles/pages/sessions.css

@@ -54,6 +54,70 @@
 	}
 }
 
+/* Session options dropdown */
+.session-options {
+	position: relative;
+}
+
+.session-options-dropdown {
+	position: absolute;
+	bottom: calc(100% + 0.25rem);
+	right: 0;
+	z-index: 100;
+	min-width: 12rem;
+	background: var(--surface);
+	border: 1px solid var(--border);
+	border-radius: 0.5rem;
+	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+	overflow: hidden;
+	animation: dropdown-in 0.12s ease-out;
+}
+
+@keyframes dropdown-in {
+	from {
+		opacity: 0;
+		transform: translateY(4px);
+	}
+	to {
+		opacity: 1;
+		transform: translateY(0);
+	}
+}
+
+.session-option-item {
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+	width: 100%;
+	padding: var(--space-2) var(--space-3);
+	font-size: 0.875rem;
+	color: var(--text);
+	background: transparent;
+	border: none;
+	cursor: pointer;
+	white-space: nowrap;
+}
+
+.session-option-item:hover {
+	background: var(--surface-hover, rgba(0, 0, 0, 0.05));
+}
+
+.session-option-item.danger-text {
+	color: var(--danger);
+}
+
+.session-option-item.danger-text:hover {
+	background: var(--danger-subtle, rgba(239, 68, 68, 0.08));
+}
+
+.session-card-actions {
+	display: flex;
+	align-items: center;
+	gap: var(--space-2);
+	padding-top: var(--space-3);
+	border-top: 1px solid var(--color-border);
+}
+
 .session-card-actions.mobile {
 	display: flex;
 	gap: var(--space-2);