feat(engine): add weekly goals with ISO-week rollover and +75 XP bonus

Phase 6 part 2b:
- solitaire_data::weekly defines WeeklyGoalKind, WeeklyGoalDef,
  WeeklyGoalContext, current_iso_week_key, and three starter goals
  (5 wins, 3 no-undo wins, 3 fast wins).
- PlayerProgress gains weekly_goal_week_iso, roll_weekly_goals_if_new_week,
  and record_weekly_progress (returns true exactly once per goal completion).
- WeeklyGoalsPlugin evaluates GameWonEvent against WEEKLY_GOALS, rolls the
  week if needed, increments matching counters, awards WEEKLY_GOAL_XP for
  newly-completed goals, persists progress, and fires
  WeeklyGoalCompletedEvent.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

solitaire_data/src/lib.rs

@@ -51,3 +51,9 @@ pub use progress::{
     daily_seed_for, level_for_xp, load_progress_from, progress_file_path, save_progress_to,
     xp_for_win, PlayerProgress,
 };
+
+pub mod weekly;
+pub use weekly::{
+    current_iso_week_key, weekly_goal_by_id, WeeklyGoalContext, WeeklyGoalDef, WeeklyGoalKind,
+    WEEKLY_GOALS, WEEKLY_GOAL_XP,
+};

solitaire_data/src/progress.rs

@@ -60,6 +60,11 @@ pub struct PlayerProgress {
     pub daily_challenge_last_completed: Option<NaiveDate>,
     pub daily_challenge_streak: u32,
     pub weekly_goal_progress: HashMap<String, u32>,
+    /// ISO week key (e.g. `"2026-W17"`) the current `weekly_goal_progress`
+    /// counters belong to. When the engine sees a different week it clears
+    /// progress and updates this field.
+    #[serde(default)]
+    pub weekly_goal_week_iso: Option<String>,
     pub unlocked_card_backs: Vec<usize>,
     pub unlocked_backgrounds: Vec<usize>,
     pub last_modified: DateTime<Utc>,
@@ -73,6 +78,7 @@ impl Default for PlayerProgress {
             daily_challenge_last_completed: None,
             daily_challenge_streak: 0,
             weekly_goal_progress: HashMap::new(),
+            weekly_goal_week_iso: None,
             unlocked_card_backs: vec![0],   // back #0 always available
             unlocked_backgrounds: vec![0],  // background #0 always available
             last_modified: DateTime::UNIX_EPOCH,
@@ -96,6 +102,32 @@ impl PlayerProgress {
         self.level > prev_level
     }
 
+    /// Reset weekly-goal progress when the ISO week has rolled over.
+    /// No-op if the stored week key already matches `current`.
+    pub fn roll_weekly_goals_if_new_week(&mut self, current: &str) -> bool {
+        if self.weekly_goal_week_iso.as_deref() == Some(current) {
+            return false;
+        }
+        self.weekly_goal_progress.clear();
+        self.weekly_goal_week_iso = Some(current.to_string());
+        self.last_modified = Utc::now();
+        true
+    }
+
+    /// Increment progress for `goal_id` by 1, capped at `target`.
+    /// Returns `true` if this call brought the counter from below `target`
+    /// to at-or-above `target` (i.e. just completed the goal).
+    pub fn record_weekly_progress(&mut self, goal_id: &str, target: u32) -> bool {
+        let entry = self.weekly_goal_progress.entry(goal_id.to_string()).or_insert(0);
+        if *entry >= target {
+            // Already complete — do not over-count.
+            return false;
+        }
+        *entry = entry.saturating_add(1);
+        self.last_modified = Utc::now();
+        *entry >= target
+    }
+
     /// Record a daily-challenge completion for `date`.
     ///
     /// - First completion ever, or a gap of more than one day: streak resets to 1.
@@ -323,6 +355,48 @@ mod tests {
         assert_eq!(p.daily_challenge_streak, 1);
     }
 
+    // --- Weekly goals ---
+
+    #[test]
+    fn first_week_roll_initializes_key_and_returns_true() {
+        let mut p = PlayerProgress::default();
+        let rolled = p.roll_weekly_goals_if_new_week("2026-W17");
+        assert!(rolled);
+        assert_eq!(p.weekly_goal_week_iso.as_deref(), Some("2026-W17"));
+    }
+
+    #[test]
+    fn same_week_roll_is_noop() {
+        let mut p = PlayerProgress::default();
+        p.roll_weekly_goals_if_new_week("2026-W17");
+        p.weekly_goal_progress.insert("g1".into(), 3);
+        let rolled = p.roll_weekly_goals_if_new_week("2026-W17");
+        assert!(!rolled);
+        assert_eq!(p.weekly_goal_progress.get("g1"), Some(&3));
+    }
+
+    #[test]
+    fn new_week_roll_clears_progress_and_updates_key() {
+        let mut p = PlayerProgress::default();
+        p.roll_weekly_goals_if_new_week("2026-W17");
+        p.weekly_goal_progress.insert("g1".into(), 3);
+        let rolled = p.roll_weekly_goals_if_new_week("2026-W18");
+        assert!(rolled);
+        assert!(p.weekly_goal_progress.is_empty());
+        assert_eq!(p.weekly_goal_week_iso.as_deref(), Some("2026-W18"));
+    }
+
+    #[test]
+    fn record_weekly_progress_returns_true_only_on_completion_step() {
+        let mut p = PlayerProgress::default();
+        assert!(!p.record_weekly_progress("g1", 3));
+        assert!(!p.record_weekly_progress("g1", 3));
+        assert!(p.record_weekly_progress("g1", 3), "third tick completes");
+        // Further ticks should not re-fire completion.
+        assert!(!p.record_weekly_progress("g1", 3));
+        assert_eq!(p.weekly_goal_progress.get("g1"), Some(&3));
+    }
+
     #[test]
     fn same_day_completion_is_idempotent() {
         let mut p = PlayerProgress::default();

solitaire_data/src/weekly.rs

@@ -0,0 +1,148 @@
+//! Weekly goal definitions and helpers.
+//!
+//! Goals reset every ISO week. Engine evaluates them on `GameWonEvent` and
+//! increments matching counters in `PlayerProgress::weekly_goal_progress`.
+
+use chrono::{Datelike, NaiveDate};
+
+/// XP awarded each time a weekly goal is just completed.
+pub const WEEKLY_GOAL_XP: u64 = 75;
+
+/// What kind of game outcome counts as progress toward this goal.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum WeeklyGoalKind {
+    /// Any win counts.
+    WinGame,
+    /// A win without using `undo` counts.
+    WinWithoutUndo,
+    /// A win in strictly fewer than `seconds` seconds counts.
+    WinUnder { seconds: u64 },
+}
+
+/// Static metadata for a single weekly goal.
+#[derive(Debug, Clone, Copy)]
+pub struct WeeklyGoalDef {
+    pub id: &'static str,
+    pub description: &'static str,
+    pub target: u32,
+    pub kind: WeeklyGoalKind,
+}
+
+/// Per-event facts a goal needs to decide whether it matched.
+#[derive(Debug, Clone, Copy)]
+pub struct WeeklyGoalContext {
+    pub time_seconds: u64,
+    pub used_undo: bool,
+}
+
+impl WeeklyGoalDef {
+    /// Returns `true` if this win event counts as one tick of progress
+    /// toward this goal.
+    pub fn matches(&self, ctx: &WeeklyGoalContext) -> bool {
+        match self.kind {
+            WeeklyGoalKind::WinGame => true,
+            WeeklyGoalKind::WinWithoutUndo => !ctx.used_undo,
+            WeeklyGoalKind::WinUnder { seconds } => ctx.time_seconds < seconds,
+        }
+    }
+}
+
+/// All currently-active weekly goals.
+pub const WEEKLY_GOALS: &[WeeklyGoalDef] = &[
+    WeeklyGoalDef {
+        id: "weekly_5_wins",
+        description: "Win 5 games this week",
+        target: 5,
+        kind: WeeklyGoalKind::WinGame,
+    },
+    WeeklyGoalDef {
+        id: "weekly_3_no_undo",
+        description: "Win 3 games without undo this week",
+        target: 3,
+        kind: WeeklyGoalKind::WinWithoutUndo,
+    },
+    WeeklyGoalDef {
+        id: "weekly_3_fast",
+        description: "Win 3 games in under 3 minutes this week",
+        target: 3,
+        kind: WeeklyGoalKind::WinUnder { seconds: 180 },
+    },
+];
+
+/// Stable identifier for the ISO week containing `date`, e.g. `"2026-W17"`.
+/// Same string for every player worldwide on the same calendar week.
+pub fn current_iso_week_key(date: NaiveDate) -> String {
+    let iso = date.iso_week();
+    format!("{}-W{:02}", iso.year(), iso.week())
+}
+
+/// Look up a weekly-goal definition by id.
+pub fn weekly_goal_by_id(id: &str) -> Option<&'static WeeklyGoalDef> {
+    WEEKLY_GOALS.iter().find(|g| g.id == id)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn ctx(time: u64, undo: bool) -> WeeklyGoalContext {
+        WeeklyGoalContext {
+            time_seconds: time,
+            used_undo: undo,
+        }
+    }
+
+    #[test]
+    fn all_goal_ids_are_unique() {
+        let mut ids: Vec<&str> = WEEKLY_GOALS.iter().map(|g| g.id).collect();
+        ids.sort();
+        let len = ids.len();
+        ids.dedup();
+        assert_eq!(ids.len(), len);
+    }
+
+    #[test]
+    fn win_game_always_matches() {
+        let g = weekly_goal_by_id("weekly_5_wins").unwrap();
+        assert!(g.matches(&ctx(60, false)));
+        assert!(g.matches(&ctx(99999, true)));
+    }
+
+    #[test]
+    fn no_undo_only_matches_clean_wins() {
+        let g = weekly_goal_by_id("weekly_3_no_undo").unwrap();
+        assert!(g.matches(&ctx(120, false)));
+        assert!(!g.matches(&ctx(120, true)));
+    }
+
+    #[test]
+    fn fast_only_matches_under_3_minutes() {
+        let g = weekly_goal_by_id("weekly_3_fast").unwrap();
+        assert!(g.matches(&ctx(60, true)));
+        assert!(g.matches(&ctx(179, true)));
+        assert!(!g.matches(&ctx(180, true)));
+        assert!(!g.matches(&ctx(300, false)));
+    }
+
+    #[test]
+    fn iso_week_key_is_stable_within_a_week() {
+        let monday = NaiveDate::from_ymd_opt(2026, 4, 20).unwrap(); // 2026-W17 Mon
+        let sunday = NaiveDate::from_ymd_opt(2026, 4, 26).unwrap(); // 2026-W17 Sun
+        assert_eq!(current_iso_week_key(monday), current_iso_week_key(sunday));
+    }
+
+    #[test]
+    fn iso_week_key_differs_across_weeks() {
+        let w17 = NaiveDate::from_ymd_opt(2026, 4, 20).unwrap();
+        let w18 = NaiveDate::from_ymd_opt(2026, 4, 27).unwrap();
+        assert_ne!(current_iso_week_key(w17), current_iso_week_key(w18));
+    }
+
+    #[test]
+    fn iso_week_key_format_includes_year_and_week() {
+        let d = NaiveDate::from_ymd_opt(2026, 4, 20).unwrap();
+        let key = current_iso_week_key(d);
+        assert!(key.starts_with("2026-W"));
+        assert_eq!(key.len(), 8);
+    }
+}