feat: add fuzzy autocomplete and NL quick-add for invoice line items

- Description field now shows a fuzzy-matched dropdown of past line items
  (description, hours, rate) as you type via Fuse.js — zero server cost
- Selecting a suggestion pre-fills description, hours, and rate in one click
- NL quick-add bar lets you type e.g. "3hrs web design @120" + Enter to
  append a fully-parsed line item without clicking through fields
- New tRPC query `getLineItemHistory` returns deduplicated past line items
  for the current user, ordered by recency
- New `parseLineItem` utility handles hours/rate extraction via regex

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/parse-line-item.ts

@@ -0,0 +1,30 @@
+export interface ParsedLineItem {
+  description: string;
+  hours: number | null;
+  rate: number | null;
+}
+
+export function parseLineItem(input: string): ParsedLineItem {
+  let text = input.trim();
+  let hours: number | null = null;
+  let rate: number | null = null;
+
+  // Extract hours: "3h", "3hr", "3hrs", "3 hours", "3.5hours"
+  const hoursMatch = /(\d+\.?\d*)\s*h(?:ours?|rs?)\b/i.exec(text);
+  if (hoursMatch?.[0] && hoursMatch[1]) {
+    hours = parseFloat(hoursMatch[1]);
+    text = text.replace(hoursMatch[0], " ").trim();
+  }
+
+  // Extract rate: "@120", "@$120", "at 120", "at $120", "$120/hr", "$120ph"
+  const rateMatch = /(?:@\s*\$?|at\s+\$?)(\d+\.?\d*)|(\$\d+\.?\d*)(?:\/h(?:rs?)?|ph)?\b/i.exec(text);
+  if (rateMatch?.[0]) {
+    const rawRate = rateMatch[1] ?? rateMatch[2] ?? "";
+    rate = parseFloat(rawRate.replace("$", ""));
+    text = text.replace(rateMatch[0], " ").trim();
+  }
+
+  const description = text.replace(/\s+/g, " ").replace(/^[\s,]+|[\s,]+$/g, "").trim();
+
+  return { description: description || input.trim(), hours, rate };
+}