Phase 20: achievement system

18 data-driven achievements (achievements.json) across 8 trigger categories:
matches_played, matches_won, goals_scored, packs_opened, sbcs_completed,
cards_owned, level, objectives_completed, drafts_completed. Rarities span
common → epic. Coin rewards range from 500 (first_match) to 6000 (win_50).

check_and_unlock() queries the relevant metric from existing tables, skips
already-earned achievements via INSERT OR IGNORE, grants coin rewards, and
fires a persistent notification per unlock. Trigger values are cached per
call to avoid redundant DB round-trips for same-trigger achievements.

Checks run automatically after every match result (all triggers), every
pack open (packs_opened), and every successful SBC submission (sbcs_completed).

GET /achievements returns all definitions annotated with unlocked/unlocked_at,
plus earned and total counts. POST /matches/result response gains an
achievements_unlocked array (empty when nothing new unlocked).

AppState gains achievement_defs (Arc<Vec<AchievementDefinition>>) loaded
from data/achievements/**/*.json at startup — same pattern as obj_defs.

5 new tests: list endpoint, first_match unlock, first_win unlock, no-dup
guard, coin reward verification. Core now at 82 tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/services/match_service.rs

@@ -2,11 +2,12 @@ use crate::{
     db::Pool,
     error::AppResult,
     models::{
+        achievement::AchievementDefinition,
         card::OwnedCard,
         match_result::{Match, MatchRewardResult, SubmitMatchRequest},
         objective::ObjectiveDefinition,
     },
-    services::{card_db::CardDb, club, notification, objective, profile, season as season_svc, statistics},
+    services::{achievement, card_db::CardDb, club, notification, objective, profile, season as season_svc, statistics},
 };
 use rand::{seq::SliceRandom, Rng};
 
@@ -91,6 +92,7 @@ pub async fn process_match(
     club_id: &str,
     req: &SubmitMatchRequest,
     obj_defs: &[ObjectiveDefinition],
+    ach_defs: &[AchievementDefinition],
 ) -> AppResult<MatchRewardResult> {
     let outcome = if req.goals_for > req.goals_against {
         "win"
@@ -210,6 +212,11 @@ pub async fn process_match(
         let _ = notification::create(pool, "season_end", "Season complete!", &body).await;
     }
 
+    let achievements_unlocked =
+        achievement::check_and_unlock(pool, ach_defs, profile_id, club_id)
+            .await
+            .unwrap_or_default();
+
     Ok(MatchRewardResult {
         match_record,
         coins_awarded: coins,
@@ -218,6 +225,7 @@ pub async fn process_match(
         expired_loans,
         season_end,
         level_ups,
+        achievements_unlocked,
     })
 }