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>

packages/api/src/router/entitlement.ts

@@ -6,6 +6,7 @@
 import { VacationType, VacationStatus } from "@planarchy/db";
 import { TRPCError } from "@trpc/server";
 import { z } from "zod";
+import { RESOURCE_BRIEF_SELECT } from "../db/selects.js";
 import { createTRPCRouter, adminProcedure, managerProcedure, protectedProcedure } from "../trpc.js";
 
 /** Types that consume from annual leave balance */
@@ -266,7 +267,7 @@ export const entitlementRouter = createTRPCRouter({
           isActive: true,
           ...(input.chapter ? { chapter: input.chapter } : {}),
         },
-        select: { id: true, displayName: true, eid: true, chapter: true },
+        select: { ...RESOURCE_BRIEF_SELECT, chapter: true },
         orderBy: [{ chapter: "asc" }, { displayName: "asc" }],
       });