feat(profile): "set your city" gamification box → one-time 500-coin reward

- New searchable city picker (src/lib/iran-cities.ts, ~60 Iranian cities,
  fa/en search) shown as a gold reward card at the top of the profile Basic tab.
- First time a non-empty city is set, the player earns 500 coins (CITY_REWARD),
  granted server-authoritatively. Collapses to a compact summary afterwards with
  a "change city" option (no re-reward).
- Frontend: UserProfile.city + cityRewardClaimed; mock-service grants on first
  set; session/service updateProfile accept `city`; celebratory toast + sfx.
- Backend (.NET): ProfileDto.City/CityRewardClaimed (JSON blob → no migration);
  ProfileService.Update grants +500 once and writes a "city" ledger entry.
- i18n: city.* keys (fa + en).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/online/gamification.ts

@@ -803,3 +803,8 @@ export const DAILY_REWARDS = [100, 150, 200, 300, 400, 600, 1500];
 export function dailyRewardFor(day: number): number {
   return DAILY_REWARDS[Math.min(day, DAILY_REWARDS.length) - 1] ?? 100;
 }
+
+/* ----------------------- Profile-completion reward ----------------------- */
+
+/** One-time coin reward for setting your city on the profile. */
+export const CITY_REWARD = 500;

src/lib/online/mock-service.ts

@@ -6,6 +6,7 @@ import {
   ACHIEVEMENTS,
   CARD_BACKS,
   CARD_FRONTS,
+  CITY_REWARD,
   REACTION_PACKS,
   STICKER_PACKS,
   TITLES,
@@ -362,7 +363,13 @@ export class MockOnlineService implements OnlineService {
 
   async updateProfile(patch: Parameters<OnlineService["updateProfile"]>[0]) {
     const p = await this.getProfile();
-    this.profile = { ...p, ...patch };
+    const next = { ...p, ...patch };
+    // One-time reward: first time the player sets a (non-empty) city → +500 coins.
+    if (patch.city && patch.city.trim() && !p.cityRewardClaimed) {
+      next.coins = p.coins + CITY_REWARD;
+      next.cityRewardClaimed = true;
+    }
+    this.profile = next;
     this.saveProfile();
     return this.profile;
   }

src/lib/online/service.ts

@@ -56,7 +56,7 @@ export interface OnlineService {
       Pick<
         UserProfile,
         | "displayName" | "avatar" | "avatarImage" | "title" | "cardFront" | "cardBack"
-        | "gender" | "socials" | "socialsVisibility"
+        | "gender" | "city" | "socials" | "socialsVisibility"
       >
     >
   ): Promise<UserProfile>;

src/lib/online/types.ts

@@ -83,6 +83,8 @@ export interface UserProfile {
 
   // social
   gender?: Gender;
+  city?: string; // selected city id (see IRAN_CITIES)
+  cityRewardClaimed?: boolean; // true once the one-time "set your city" reward was granted
   socials?: SocialLinks;
   socialsVisibility?: SocialVisibility; // default "public"