feat(budget): add "Fuel" and "Parking" expense categories

- Adds two new fixed budget categories: fuel ("Fuel") and parkings
  ("Parking"), alongside the existing set (Accommodation, Food & drink,
  Groceries, Transport, Flights, Activities, Sightseeing, Shopping,
  Fees & tickets, Health, Tips, Other).
- Icon/color metadata added for both (Fuel and ParkingCircle from
  lucide-react), plus legacy free-text aliases (gas/petrol->fuel,
  parking->parkings) for existing/imported expense rows.
- Label strings added for all 23 supported locales.
- Adds test coverage for the new categories and legacy alias mapping.

client/src/components/Budget/costsCategories.test.ts

@@ -0,0 +1,34 @@
+import { describe, it, expect } from 'vitest'
+import { COST_CATEGORIES } from '@trek/shared'
+import { COST_CAT_META, COST_CATEGORY_LIST, catMeta } from './costsCategories'
+
+describe('COST_CAT_META', () => {
+  it('has metadata for every fixed category, including fuel and parkings', () => {
+    for (const key of COST_CATEGORIES) {
+      expect(COST_CAT_META[key]).toBeDefined()
+      expect(COST_CAT_META[key].key).toBe(key)
+    }
+  })
+
+  it('derives COST_CATEGORY_LIST in the same order as COST_CATEGORIES', () => {
+    expect(COST_CATEGORY_LIST.map(m => m.key)).toEqual([...COST_CATEGORIES])
+  })
+})
+
+describe('catMeta', () => {
+  it('resolves fuel and parkings directly', () => {
+    expect(catMeta('fuel').key).toBe('fuel')
+    expect(catMeta('parkings').key).toBe('parkings')
+  })
+
+  it('maps legacy/free-text aliases to the new categories', () => {
+    expect(catMeta('gas').key).toBe('fuel')
+    expect(catMeta('petrol').key).toBe('fuel')
+    expect(catMeta('parking').key).toBe('parkings')
+  })
+
+  it('falls back to other for unknown categories', () => {
+    expect(catMeta('made-up-category').key).toBe('other')
+    expect(catMeta(null).key).toBe('other')
+  })
+})

client/src/components/Budget/costsCategories.tsx

@@ -1,4 +1,4 @@
-import { Hotel, Utensils, ShoppingCart, Bus, Plane, Ticket, Camera, ShoppingBag, FileText, HeartPulse, Coins, MoreHorizontal } from 'lucide-react'
+import { Hotel, Utensils, ShoppingCart, Bus, Plane, Ticket, Camera, ShoppingBag, FileText, HeartPulse, Coins, MoreHorizontal, Fuel, ParkingCircle } from 'lucide-react'
 import type { LucideIcon } from 'lucide-react'
 import { COST_CATEGORIES, type CostCategory } from '@trek/shared'
 
@@ -27,6 +27,8 @@ export const COST_CAT_META: Record<CostCategory, CostCategoryMeta> = {
   fees:          { key: 'fees',          labelKey: 'costs.cat.fees',          Icon: FileText, color: '#475569' },
   health:        { key: 'health',        labelKey: 'costs.cat.health',        Icon: HeartPulse, color: '#dc2626' },
   tips:          { key: 'tips',          labelKey: 'costs.cat.tips',          Icon: Coins, color: '#d97706' },
+  fuel:          { key: 'fuel',          labelKey: 'costs.cat.fuel',          Icon: Fuel, color: '#f59e0b' },
+  parkings:      { key: 'parkings',      labelKey: 'costs.cat.parkings',      Icon: ParkingCircle, color: '#3b82f6' },
   other:         { key: 'other',         labelKey: 'costs.cat.other',         Icon: MoreHorizontal, color: '#6b7280' },
 }
 
@@ -51,6 +53,8 @@ const LEGACY_CATEGORY_MAP: Record<string, CostCategory> = {
   fee: 'fees', fees: 'fees',
   health: 'health', medical: 'health',
   tip: 'tips', tips: 'tips',
+  gas: 'fuel', fuel: 'fuel', petrol: 'fuel',
+  parking: 'parkings', parkings: 'parkings',
   other: 'other', misc: 'other',
 }