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/app/(app)/projects/ProjectsClient.tsx

@@ -2,7 +2,7 @@
 
 import { useState, useEffect, useCallback, useMemo, useRef } from "react";
 import { createPortal } from "react-dom";
-import { formatDate } from "~/lib/format.js";
+import { formatDate, formatMoney } from "~/lib/format.js";
 import type { Project, ColumnDef } from "@planarchy/shared";
 import { ProjectStatus, PROJECT_COLUMNS, BlueprintTarget } from "@planarchy/shared";
 import Link from "next/link";
@@ -400,7 +400,7 @@ export function ProjectsClient() {
         return (
           <td key={col.key} className="px-4 py-3 min-w-[120px]">
             <div className="mb-0.5 text-sm text-gray-900 dark:text-gray-100">
-              {(project.budgetCents / 100).toLocaleString("de-DE", { minimumFractionDigits: 0 })} €
+              {formatMoney(project.budgetCents)}
             </div>
             <BudgetBar utilizationPercent={project.utilizationPercent ?? 0} budgetCents={project.budgetCents} />
           </td>