feat: theme dropdown with system preference and comprehensive bottle-type fixes (#138)

- Replace dark/light toggle with Light/Dark/System dropdown menu
- System theme follows OS prefers-color-scheme setting
- Apply theme dropdown to shared schedule page
- Fix 7 packageType (bottle) bugs across stock calc, share, refills, export/import
- Fix planner bottle-type stock calculation and display
- Fix dailyRate double-counting with per-intake takenBy
- Fix About modal update check stale caching
- Fix intake reminder past-intake seeding and push title
- Fix phantom DB path in drizzle.config.ts
- Fix mobile dose field visibility
- Make medication name clickable in dashboard reminder bar
- Improve planner checkbox UX with inline tooltip
- Add 20+ new tests covering all fixes

frontend/src/styles.css

@@ -152,6 +152,90 @@ body.modal-open {
 	background: rgba(47, 134, 246, 0.12);
 }
 
+/* =============================================================================
+   Theme Dropdown Menu
+   ============================================================================= */
+.theme-menu {
+	position: relative;
+}
+
+.theme-dropdown {
+	position: absolute;
+	top: calc(100% + 0.5rem);
+	right: 0;
+	min-width: 160px;
+	background: rgba(15, 23, 42, 0.85);
+	backdrop-filter: blur(12px);
+	-webkit-backdrop-filter: blur(12px);
+	border: 1px solid rgba(255, 255, 255, 0.12);
+	border-radius: 12px;
+	box-shadow:
+		0 12px 32px rgba(0, 0, 0, 0.4),
+		inset 0 0 0 1px rgba(255, 255, 255, 0.05);
+	opacity: 0;
+	visibility: hidden;
+	transform: translateY(-6px) scale(0.95);
+	transition: all 0.2s ease;
+	z-index: 1000;
+	overflow: hidden;
+	padding: 0.375rem;
+}
+
+[data-theme="light"] .theme-dropdown {
+	background: rgba(255, 255, 255, 0.85);
+	border: 1px solid rgba(0, 0, 0, 0.08);
+	box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12);
+}
+
+.theme-menu.open .theme-dropdown {
+	opacity: 1;
+	visibility: visible;
+	transform: translateY(0) scale(1);
+}
+
+.theme-dropdown-item {
+	display: flex;
+	align-items: center;
+	gap: 0.75rem;
+	width: 100%;
+	padding: 0.625rem 0.75rem;
+	border: none;
+	background: none;
+	color: var(--text-primary);
+	font-size: 0.875rem;
+	cursor: pointer;
+	border-radius: 8px;
+	transition: background 0.15s ease;
+	text-align: left;
+	box-shadow: none;
+}
+
+.theme-dropdown-item:hover {
+	background: rgba(59, 130, 246, 0.15);
+}
+
+.theme-dropdown-item.active {
+	color: var(--accent-primary);
+}
+
+.theme-dropdown-item svg {
+	width: 18px;
+	height: 18px;
+	flex-shrink: 0;
+	opacity: 0.7;
+}
+
+.theme-dropdown-item.active svg {
+	opacity: 1;
+	color: var(--accent-primary);
+}
+
+.theme-check {
+	margin-left: auto;
+	font-size: 0.8rem;
+	opacity: 0.8;
+}
+
 .hero-title {
 	display: flex;
 	align-items: center;
@@ -1024,12 +1108,14 @@ textarea.auto-resize {
 
 .dose-input-group input {
 	flex: 1;
-	min-width: 0;
+	min-width: 100px;
 }
 
 .dose-unit-select {
 	width: auto;
-	min-width: 80px;
+	min-width: unset;
+	max-width: 120px;
+	flex-shrink: 0;
 	padding: 0.5rem 0.75rem;
 	background: var(--bg-primary);
 	border: 1px solid var(--border-primary);
@@ -2019,11 +2105,12 @@ textarea.auto-resize {
 	text-transform: uppercase;
 	letter-spacing: 0.04em;
 }
-.planner-checkbox {
+.planner label.planner-checkbox {
 	grid-column: 1 / -1;
 	display: flex;
 	flex-direction: row;
 	align-items: center;
+	flex-wrap: nowrap;
 	gap: 0.75rem;
 	color: var(--text-secondary);
 	font-size: 0.875rem;
@@ -4614,7 +4701,6 @@ a.about-version-link:hover {
 .about-update-section {
 	padding: 1.25rem 1.5rem;
 	border-bottom: 1px solid var(--border-primary);
-	min-height: 148px;
 }
 
 .about-update-btn {
@@ -4713,13 +4799,6 @@ a.about-version-link:hover {
 	background: var(--accent-hover);
 }
 
-.update-last-checked {
-	display: block;
-	margin-top: 0.5rem;
-	font-size: 0.75rem;
-	opacity: 0.8;
-}
-
 .about-links {
 	padding: 1.25rem 1.5rem;
 	border-bottom: 1px solid var(--border-primary);