refactor(utils→import): move single-consumer date/html/level helpers, inline field into fonts

Finding 4 — consumer-count verification:
  @reactive-resume/utils/date  → 1 consumer (packages/import/src/json-resume.tsx)
  @reactive-resume/utils/html  → 1 consumer (packages/import/src/json-resume.tsx)
  @reactive-resume/utils/level → 1 consumer (packages/import/src/json-resume.tsx)
  @reactive-resume/utils/url   → 4 consumers (auth, api/ai, import, server) — SKIPPED, stays in utils
  @reactive-resume/utils/field → 1 consumer (packages/fonts/src/index.ts)

Move date/html/level source + test files into packages/import and update json-resume.tsx imports.
Inline the two-line unique() helper into fonts/src/index.ts and drop the ./field subpath.
Drop the three moved subpaths from packages/utils exports.

Claude-Session: https://claude.ai/code/session_012Bnvt1MghwHj4qQRxuQUGa

packages/import/src/date.ts

@@ -0,0 +1,51 @@
+// ponytail: Intl replaces the 12-line MONTH_NAMES array; pinned to en-US so output is stable
+const fmt = new Intl.DateTimeFormat("en-US", { month: "long" });
+
+function getMonthName(month: string | undefined): string {
+	const index = Number.parseInt(month ?? "1", 10) - 1;
+	if (index < 0 || index > 11) return "undefined";
+	return fmt.format(new Date(2000, index, 1));
+}
+
+/**
+ * Formats a partial ISO 8601 date string (YYYY, YYYY-MM, or YYYY-MM-DD)
+ * into a human-readable format like "January 2024" or "January 15, 2024".
+ */
+export function formatDate(date: string, includeDay = false): string {
+	const parts = date.split("-");
+
+	if (parts.length >= 2) {
+		const [year, month] = parts;
+		const monthName = getMonthName(month);
+
+		if (parts.length === 3 && includeDay) {
+			return `${monthName} ${parts[2]}, ${year}`;
+		}
+
+		return `${monthName} ${year}`;
+	}
+
+	// YYYY only
+	return date;
+}
+
+/**
+ * Formats a date range from start and end dates.
+ * Returns "Start - End", "Start - Present" if no end, or just the end date if no start.
+ */
+export function formatPeriod(startDate?: string, endDate?: string): string {
+	if (!startDate && !endDate) return "";
+	if (!startDate) return endDate || "";
+	if (!endDate) return `${formatDate(startDate)} - Present`;
+
+	return `${formatDate(startDate)} - ${formatDate(endDate)}`;
+}
+
+/**
+ * Formats a single date with day included (e.g., "January 15, 2024").
+ * Falls back to month-year or year-only for partial dates.
+ */
+export function formatSingleDate(date?: string): string {
+	if (!date) return "";
+	return formatDate(date, true);
+}