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/project-planning-read-model.ts

@@ -1,6 +1,7 @@
 import { buildSplitAllocationReadModel } from "@planarchy/application";
 import type { PrismaClient } from "@planarchy/db";
 import { AllocationStatus } from "@planarchy/shared";
+import { ROLE_BRIEF_SELECT } from "../db/selects.js";
 
 export const PROJECT_PLANNING_ALLOCATION_INCLUDE = {
   resource: {
@@ -31,7 +32,7 @@ export const PROJECT_PLANNING_ALLOCATION_INCLUDE = {
     },
   },
   roleEntity: {
-    select: { id: true, name: true, color: true },
+    select: ROLE_BRIEF_SELECT,
   },
 } as const;