Unify time tracking on server-backed entries with updateRunning.

Consolidates dashboard and invoice timers onto shared time-entry APIs so clock-in state, invoice linking, and clock-out flow stay consistent across surfaces.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/time-clock.ts

@@ -0,0 +1,41 @@
+export type ClockOutOutcome =
+  | "linked_to_invoice"
+  | "saved_no_invoice"
+  | "saved_no_client"
+  | "zero_hours";
+
+export function computeTrackedHours(startedAt: Date, endedAt: Date): number {
+  const seconds = Math.floor((endedAt.getTime() - startedAt.getTime()) / 1000);
+  return Math.max(0.25, Math.ceil(seconds / 900) * 0.25);
+}
+
+export function formatElapsedSeconds(seconds: number): string {
+  const h = Math.floor(seconds / 3600);
+  const m = Math.floor((seconds % 3600) / 60);
+  const s = seconds % 60;
+  return [h, m, s].map((v) => String(v).padStart(2, "0")).join(":");
+}
+
+export function describeClockOutOutcome(input: {
+  outcome: ClockOutOutcome;
+  hours: number;
+  rate: number;
+  invoice?: { invoicePrefix: string; invoiceNumber: string } | null;
+}): string {
+  const amount = input.hours * input.rate;
+
+  switch (input.outcome) {
+    case "linked_to_invoice":
+      if (input.invoice) {
+        const label = `${input.invoice.invoicePrefix}${input.invoice.invoiceNumber}`;
+        return `Added ${input.hours}h @ $${input.rate}/hr ($${amount.toFixed(2)}) to invoice ${label}`;
+      }
+      return `Added ${input.hours}h to invoice`;
+    case "saved_no_invoice":
+      return `Saved ${input.hours}h — no open invoice found for this client. Pick an invoice on the time clock or create one.`;
+    case "saved_no_client":
+      return `Saved ${input.hours}h — assign a client and invoice to bill this time.`;
+    case "zero_hours":
+      return "Timer stopped (less than minimum billable increment).";
+  }
+}