refactor: add date utility for consistent UTC handling

src/lib/shared/dates.ts

@@ -0,0 +1,51 @@
+/**
+ * Date utilities for handling SQLite timestamps
+ *
+ * SQLite stores timestamps from CURRENT_TIMESTAMP as UTC in the format
+ * "YYYY-MM-DD HH:MM:SS" (no timezone indicator). JavaScript's Date constructor
+ * interprets strings without timezone info as local time, causing incorrect
+ * display.
+ *
+ * These utilities normalize SQLite timestamps to proper ISO 8601 format
+ * so JavaScript correctly interprets them as UTC.
+ */
+
+/**
+ * Normalizes a SQLite timestamp to ISO 8601 format with UTC indicator.
+ * Handles both SQLite format ("YYYY-MM-DD HH:MM:SS") and ISO format.
+ *
+ * @param timestamp - SQLite or ISO timestamp string
+ * @returns ISO 8601 formatted string with Z suffix, or null if input is null/undefined
+ *
+ * @example
+ * toUTC("2026-01-17 03:21:52")     // "2026-01-17T03:21:52Z"
+ * toUTC("2026-01-17T03:21:52")     // "2026-01-17T03:21:52Z"
+ * toUTC("2026-01-17T03:21:52Z")    // "2026-01-17T03:21:52Z" (unchanged)
+ * toUTC(null)                      // null
+ */
+export function toUTC(timestamp: string | null | undefined): string | null {
+	if (!timestamp) return null;
+
+	// Already has Z suffix - return as-is
+	if (timestamp.endsWith('Z')) return timestamp;
+
+	// Replace space with T (SQLite format) and add Z
+	return timestamp.replace(' ', 'T') + 'Z';
+}
+
+/**
+ * Parses a SQLite timestamp into a JavaScript Date object.
+ * Normalizes the timestamp to UTC before parsing.
+ *
+ * @param timestamp - SQLite or ISO timestamp string
+ * @returns Date object, or null if input is null/undefined
+ *
+ * @example
+ * parseUTC("2026-01-17 03:21:52")  // Date object in UTC
+ * parseUTC(null)                   // null
+ */
+export function parseUTC(timestamp: string | null | undefined): Date | null {
+	const normalized = toUTC(timestamp);
+	if (!normalized) return null;
+	return new Date(normalized);
+}