refactor: consolidate duplicated code across web and API packages

- Extract shared render helpers (vacation blocks, range overlay, overbooking blink) into renderHelpers.tsx
- Centralize status badge styles and vacation color maps into status-styles.ts
- Extract dragMath.ts utility from useTimelineDrag for reuse
- Split useInvalidatePlanningViews into useInvalidateTimeline (4 queries) + useInvalidatePlanningViews (8 queries)
- Adopt findUniqueOrThrow() and Prisma select constants across API routers
- Add shared fmtEur() helper for API-side money formatting
- Wrap TimelineResourcePanel and TimelineProjectPanel with React.memo
- Fix pre-existing TS2589 deep type errors in TeamCalendar and VacationModal
- 38 files changed, reducing ~400 lines of duplicated code

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/components/projects/ProjectAssignmentsTable.tsx

@@ -2,7 +2,7 @@
 
 import { useState, useMemo } from "react";
 import { useRouter } from "next/navigation";
-import { formatDate, formatMoney } from "~/lib/format.js";
+import { formatCents, formatDate, formatMoney } from "~/lib/format.js";
 import { InfoTooltip } from "~/components/ui/InfoTooltip.js";
 import { ALLOCATION_STATUS_BADGE } from "~/lib/status-styles.js";
 import { usePermissions } from "~/hooks/usePermissions.js";
@@ -127,7 +127,7 @@ export function ProjectAssignmentsTable({ assignments }: ProjectAssignmentsTable
               </td>
               <td className="px-4 py-3 text-sm text-right text-gray-900 dark:text-gray-100">{assignment.hoursPerDay}h</td>
               <td className="px-4 py-3 text-sm text-right text-gray-900 dark:text-gray-100">
-                {(assignment.dailyCostCents / 100).toLocaleString("de-DE", { minimumFractionDigits: 2 })} €
+                {formatCents(assignment.dailyCostCents)} €
               </td>
               <td className="px-4 py-3 text-sm text-right text-gray-900 dark:text-gray-100">
                 {(countWorkingDays(assignment.startDate, assignment.endDate) * assignment.hoursPerDay).toLocaleString("de-DE", { minimumFractionDigits: 1 })}h