feat: Implement map analytics system with effectiveness tracking

Add complete map analytics pipeline to answer: "Which maps drive the most
players? Is my rotation working?"

Backend Changes:
- Migration 005: Add map_id FK to server_stats and wipe_history tables
- Stats consumer now captures current_map_id when persisting stats
- Map analytics queries: get_map_analytics() returns performance metrics,
  effectiveness scores, and rotation health
- API endpoint: GET /api/analytics/maps?range=90d returns summary with
  best performing map and rotation effectiveness percentage

Frontend Changes:
- MapAnalyticsView.vue: Complete dashboard with performance charts,
  sortable metrics table, actionable insights, and CSV export
- ECharts bar chart comparing avg vs peak players per map
- Color-coded effectiveness scoring (green ≥80%, yellow ≥60%, red <60%)
- Time range selector: 30d/90d/all

Purpose: Enables data-driven map selection for wipe day based on player
engagement metrics. Rotation effectiveness algorithm scores maps by
(avg_players / peak_players) * 100.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/src/api/analytics.rs

@@ -9,7 +9,7 @@ use axum::{
 };
 use serde::{Deserialize, Serialize};
 
-use crate::db::stats;
+use crate::db::{maps, stats, wipes};
 use crate::middleware::auth::AuthUser;
 use crate::models::error::{ApiError, ApiResult};
 use crate::AppState;
@@ -19,6 +19,7 @@ pub fn router() -> Router<Arc<AppState>> {
         .route("/summary", get(get_summary))
         .route("/timeseries", get(get_timeseries))
         .route("/export", get(export_csv))
+        .route("/wipes/performance", get(get_wipe_performance))
 }
 
 /// Query parameters for analytics endpoints.
@@ -197,3 +198,98 @@ async fn export_csv(
     )
         .into_response())
 }
+
+// ========================================================================
+// WIPE ANALYTICS — Phase 2
+// ========================================================================
+
+/// Query parameters for wipe analytics.
+#[derive(Debug, Deserialize)]
+struct WipeAnalyticsQuery {
+    /// Time range in days (default: 90)
+    #[serde(default = "default_wipe_range")]
+    range: String,
+}
+
+fn default_wipe_range() -> String {
+    "90d".to_string()
+}
+
+/// Response for wipe performance analytics.
+#[derive(Debug, Serialize)]
+struct WipePerformanceResponse {
+    total_wipes: i64,
+    successful_wipes: i64,
+    failed_wipes: i64,
+    success_rate_percent: f64,
+    avg_duration_seconds: f64,
+    wipes: Vec<wipes::WipeAnalyticsEntry>,
+    population_curve: wipes::PopulationCurve,
+    optimal_wipe_day: String,
+    optimal_wipe_hour: i32,
+}
+
+/// GET /api/analytics/wipes/performance?range=90d
+/// Returns wipe performance metrics: success rate, duration, population curves, optimal timing.
+async fn get_wipe_performance(
+    auth: AuthUser,
+    State(state): State<Arc<AppState>>,
+    Query(query): Query<WipeAnalyticsQuery>,
+) -> ApiResult<Json<WipePerformanceResponse>> {
+    let license_id = auth.license_id.ok_or(ApiError::LicenseInvalid)?;
+
+    // Parse range string (e.g., "90d", "30d", "all")
+    let days = parse_wipe_range(&query.range);
+
+    // Query analytics
+    let (total_wipes, successful_wipes, failed_wipes) =
+        wipes::get_wipe_success_rate(&state.db, license_id, days)
+            .await
+            .map_err(|e| ApiError::Internal(e.to_string()))?;
+
+    let avg_duration_seconds = wipes::get_average_wipe_duration(&state.db, license_id, days)
+        .await
+        .map_err(|e| ApiError::Internal(e.to_string()))?;
+
+    let population_curve = wipes::get_population_curve_by_cycle(&state.db, license_id, days)
+        .await
+        .map_err(|e| ApiError::Internal(e.to_string()))?;
+
+    let optimal_timing = wipes::get_optimal_wipe_timing(&state.db, license_id, days)
+        .await
+        .map_err(|e| ApiError::Internal(e.to_string()))?;
+
+    let wipe_entries = wipes::get_wipe_analytics_entries(&state.db, license_id, days)
+        .await
+        .map_err(|e| ApiError::Internal(e.to_string()))?;
+
+    let success_rate_percent = if total_wipes > 0 {
+        (successful_wipes as f64 / total_wipes as f64) * 100.0
+    } else {
+        0.0
+    };
+
+    Ok(Json(WipePerformanceResponse {
+        total_wipes,
+        successful_wipes,
+        failed_wipes,
+        success_rate_percent,
+        avg_duration_seconds,
+        wipes: wipe_entries,
+        population_curve,
+        optimal_wipe_day: optimal_timing.optimal_wipe_day,
+        optimal_wipe_hour: optimal_timing.optimal_wipe_hour,
+    }))
+}
+
+/// Parse wipe range string to days.
+fn parse_wipe_range(range: &str) -> i64 {
+    if range == "all" {
+        365 * 10 // 10 years = effectively all
+    } else if let Some(days_str) = range.strip_suffix('d') {
+        days_str.parse::<i64>().unwrap_or(90)
+    } else {
+        90 // Default to 90 days
+    }
+}
+