feat: Telegram alert on regime quadrant change (hysteresis + cooldown)

Fires once when the regime monitor shifts quadrant (regime index x early
warning), so you don't have to watch the tab. Two guards against spam:

- Hysteresis: each axis only flips once the value crosses its divider by a
  margin, so a point parked on a boundary keeps its quadrant instead of
  flip-flopping day to day.
- Cooldown: a genuine change stays quiet for a few days after the last alert.

Seeds the baseline silently on first run; reuses the existing Telegram dispatch
+ AlertLog. New per-trigger toggle in Admin → Alerts (on by default).

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

frontend/src/components/admin/AlertSettings.tsx

@@ -12,13 +12,15 @@ type TriggerKey =
   | 'qualified_enabled'
   | 'sr_proximity_enabled'
   | 'score_drop_enabled'
-  | 'digest_enabled';
+  | 'digest_enabled'
+  | 'regime_quadrant_enabled';
 
 const TRIGGERS: { key: TriggerKey; label: string; hint: string }[] = [
   { key: 'qualified_enabled', label: 'Qualified setups', hint: 'a setup newly clears the activation gate' },
   { key: 'sr_proximity_enabled', label: 'Watchlist S/R proximity', hint: 'a watched ticker nears a strong support/resistance' },
   { key: 'score_drop_enabled', label: 'Score deterioration', hint: 'a watched ticker’s composite drops sharply' },
   { key: 'digest_enabled', label: 'Daily digest', hint: 'one end-of-day summary of qualified setups' },
+  { key: 'regime_quadrant_enabled', label: 'Regime quadrant change', hint: 'the regime monitor shifts quadrant (hysteresis + cooldown)' },
 ];
 
 function Toggle({ checked, onChange, label, hint }: {
@@ -56,6 +58,7 @@ export function AlertSettings() {
     sr_proximity_enabled: true,
     score_drop_enabled: true,
     digest_enabled: true,
+    regime_quadrant_enabled: true,
   });
 
   useEffect(() => {
@@ -67,6 +70,7 @@ export function AlertSettings() {
         sr_proximity_enabled: data.sr_proximity_enabled,
         score_drop_enabled: data.score_drop_enabled,
         digest_enabled: data.digest_enabled,
+        regime_quadrant_enabled: data.regime_quadrant_enabled,
       });
     }
   }, [data]);

frontend/src/lib/types.ts

@@ -380,6 +380,7 @@ export interface AlertConfig {
   sr_proximity_enabled: boolean;
   score_drop_enabled: boolean;
   digest_enabled: boolean;
+  regime_quadrant_enabled: boolean;
 }
 
 export interface AlertTestResult {