feat: sharpen the event study — more events, fair baseline, per-event view

The first run gave only 2 events (N=2 is anecdote, not evidence) and an unfairly
weak coincident baseline, so the +42d lead couldn't be trusted. This makes the
measurement meaningful:

- More, cleaner events: default drawdown threshold 15%→10%, and dedup switched
  from "recover to the high" to a rising-edge + cooldown (40d), so distinct
  drawdowns each register instead of merging.
- Fair comparison: each indicator now warns at its OWN 80th percentile instead of
  a shared absolute 60, removing the artifact that muted the coincident baseline.
- Per-event breakdown (date · depth · breadth lead · coincident lead) so a median
  over a tiny sample can't hide an apples-to-oranges comparison — you see whether
  both warned on the same drawdown.
- Surface precision/recall (best row) + base rate per indicator — the honest edge
  read, not just lead time.

Re-run the Event Study job to regenerate the cached report in the new shape.

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

frontend/src/lib/types.ts

@@ -316,6 +316,7 @@ export interface EventStudyLeadStats {
   median_lead_days: number | null;
   events_with_signal: number;
   events_total: number;
+  warn_threshold: number;
   mean_path: { rel_day: number; value: number }[];
   signal: {
     base_rate: number;
@@ -324,6 +325,13 @@ export interface EventStudyLeadStats {
   };
 }
 
+export interface EventStudyPerEvent {
+  date: string;
+  depth_pct: number;
+  breadth_lead: number | null;
+  coincident_lead: number | null;
+}
+
 export interface EventStudyReport {
   available: boolean;
   reason?: string;
@@ -331,14 +339,16 @@ export interface EventStudyReport {
   params?: {
     benchmark: string;
     event_threshold_pct: number;
+    cooldown_days: number;
     horizon_days: number;
-    warn_threshold: number;
+    warn_percentile: number;
   };
   events?: { date: string; index: number; depth_pct: number }[];
   indicators?: {
     breadth_divergence: EventStudyLeadStats;
     coincident_price: EventStudyLeadStats;
   };
+  per_event?: EventStudyPerEvent[];
   lead_delta_days?: number | null;
   recent_breadth?: { date: string; breadth: number; divergence: number | null }[];
 }