feat: preferences, exclusion-aware planner, /onboarding (PRD §5.1, §3)

Preferences (PRD §5.1)
- @ketopath/shared: zod schemas + EXCLUSION_GROUPS, CUISINE_TAGS,
  COOKING_TIMES, FASTING_PROTOCOL_VALUES
- apps/api: GET/PATCH /me/preferences (exclusions, cuisinePreferences,
  cookingTime, fastingProtocol)
- apps/web: PreferencesForm chip-based + PreferencesSection wired into
  /profile so existing users can edit
- Plan generation now aggregates Ingredient.exclusionGroups → Recipe
  exclusionTags so matchMeals filters out excluded recipes

Onboarding (PRD §3)
- /onboarding multi-step (profile → preferences → done) with smart-jump:
  starts at the first incomplete step
- ProfileForm gains optional onSaved/saveLabel for reuse outside /profile
- Redirect chain updated: /welcome accept → /onboarding (was /profile);
  /plan, /tracking, /shopping redirect missing profiles to /onboarding
- /profile remains the editing surface for returning users

i18n
- New Onboarding + Preferences namespaces (it)

Smoke tested end-to-end: selected fish exclusion, regenerated the plan,
verified Salmone/Branzino/Tonno are filtered out and unaffected recipes
(Frittata, Pollo, Mandorle, Polpette) remain.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shared/src/index.ts

@@ -1,4 +1,5 @@
 export * from './notifications/schema.js';
+export * from './preferences/schema.js';
 export * from './nutrition/bmr.js';
 export * from './nutrition/tdee.js';
 export * from './nutrition/types.js';

packages/shared/src/preferences/schema.ts

@@ -0,0 +1,51 @@
+import { z } from 'zod';
+
+// PRD §5.1 — gruppi di esclusione legati agli ingredienti.
+// Devono coincidere con i tag su `Ingredient.exclusionGroups` nel seed
+// (vedi packages/db/prisma/seed-ingredients.ts).
+export const EXCLUSION_GROUPS = [
+  'lactose',
+  'egg',
+  'fish',
+  'nuts',
+  'gluten',
+  'pork',
+  'beef',
+] as const;
+export type ExclusionGroup = (typeof EXCLUSION_GROUPS)[number];
+
+// Tradizioni regionali italiane + low-carb internazionali.
+// Per ora informative: il matchmaking ne tiene conto solo come bonus.
+export const CUISINE_TAGS = [
+  'mediterranea',
+  'italiana',
+  'pugliese',
+  'siciliana',
+  'toscana',
+  'medio-orientale',
+  'nordica',
+] as const;
+export type CuisineTag = (typeof CUISINE_TAGS)[number];
+
+export const COOKING_TIMES = ['LOW', 'MEDIUM', 'HIGH'] as const;
+export type CookingTimeLevel = (typeof COOKING_TIMES)[number];
+
+export const FASTING_PROTOCOL_VALUES = [
+  'FOURTEEN_TEN',
+  'SIXTEEN_EIGHT',
+  'EIGHTEEN_SIX',
+  'TWENTY_FOUR',
+  'ESE_24',
+  'FIVE_TWO',
+] as const;
+
+export const preferencesPatchSchema = z
+  .object({
+    exclusions: z.array(z.enum(EXCLUSION_GROUPS)).max(EXCLUSION_GROUPS.length).optional(),
+    cuisinePreferences: z.array(z.enum(CUISINE_TAGS)).max(CUISINE_TAGS.length).optional(),
+    cookingTime: z.enum(COOKING_TIMES).optional(),
+    fastingProtocol: z.enum(FASTING_PROTOCOL_VALUES).nullable().optional(),
+  })
+  .strict();
+
+export type PreferencesPatch = z.infer<typeof preferencesPatchSchema>;