feat: Pattern Explorer — taxonomy tree + 23 historical patterns + instrument lens

- PatternExplorer.tsx: new page with two views:
    • Tree View — 6-root taxonomy (geopolitical, monetary_policy, economic,
      commodity, risk_off, market_structure) with collapsible sub-nodes;
      pattern cards appear on node selection
    • Instrument Lens — search any ticker (e.g. GLD, FXE) to see every
      pattern + scenario that references it, with matching trades highlighted
- geo_analyzer.py: PATTERN_TAXONOMY tree constant + taxonomy_path on all
  patterns; 15 new documented patterns P009-P023 (BoJ YCC, SVB crisis,
  Taiwan semis, OPEC cuts, Fed pivot, Debt ceiling, Iran nuclear, DPRK,
  VIX backwardation, ECB surprise, Extreme Fear contrarian, S. China Sea,
  European energy, CPI hot print, Flash crash)
- patterns.py: GET /api/patterns/taxonomy, GET /api/patterns/by-instrument
- database.py: taxonomy_path migration + seed_builtin_patterns updates path
- App.tsx: /patterns → PatternExplorer, /patterns/edit → PatternEditor

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

backend/routers/patterns.py

@@ -1,9 +1,10 @@
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter, HTTPException, Query
 from pydantic import BaseModel
 from typing import Optional, List, Dict, Any
 from services.database import (
     save_custom_pattern, get_custom_patterns, delete_custom_pattern, toggle_pattern_active
 )
+from services.geo_analyzer import PATTERN_TAXONOMY
 
 router = APIRouter(prefix="/api/patterns", tags=["patterns"])
 
@@ -71,3 +72,26 @@ def toggle_pattern(pat_id: str):
     """Enable or disable a pattern (works for builtin and custom)."""
     new_state = toggle_pattern_active(pat_id)
     return {"id": pat_id, "is_active": new_state}
+
+
+@router.get("/taxonomy")
+def get_taxonomy():
+    """Return the taxonomy tree + all patterns (frontend builds node→pattern mapping)."""
+    patterns = get_custom_patterns()
+    return {"tree": PATTERN_TAXONOMY, "patterns": patterns}
+
+
+@router.get("/by-instrument")
+def get_by_instrument(ticker: str = Query(..., description="Ticker / underlying to search")):
+    """Return all patterns that have a suggested_trade matching the given ticker."""
+    ticker_lower = ticker.strip().lower()
+    result = []
+    for p in get_custom_patterns():
+        trades = p.get("suggested_trades") or []
+        matching = [
+            t for t in trades
+            if ticker_lower in (t.get("underlying") or "").lower()
+        ]
+        if matching:
+            result.append({**p, "matching_trades": matching})
+    return result