feat: raise market_api rate to 20/min, add global Polygon cap at 45/min, add rate-limit API + watchlist warning

services/api/app.py

@@ -1534,6 +1534,60 @@ async def get_source_coverage_gaps():
     }
 
 
+# ---------------------------------------------------------------------------
+# System: Rate Limit Info
+# ---------------------------------------------------------------------------
+
+
+@app.get("/api/system/rate-limits")
+async def get_rate_limits():
+    """Return current rate limit configuration and usage.
+
+    Exposes the scheduler's rate limits so the frontend can calculate
+    how many tickers can be refreshed within the configured cadence.
+    """
+    from services.scheduler.app import (
+        DEFAULT_CADENCES,
+        DEFAULT_RATE_LIMITS,
+        POLYGON_GLOBAL_RATE_LIMIT,
+        POLYGON_SOURCE_TYPES,
+    )
+
+    # Count active market_api sources to report current load
+    market_count = await pool.fetchval(
+        "SELECT count(*) FROM sources WHERE active = TRUE AND source_type = 'market_api'"
+    )
+    news_count = await pool.fetchval(
+        "SELECT count(*) FROM sources WHERE active = TRUE AND source_type = 'news_api'"
+    )
+
+    market_cadence = DEFAULT_CADENCES.get("market_api", 300)
+    market_rate = DEFAULT_RATE_LIMITS.get("market_api", 20)
+
+    # How many tickers can we refresh within one cadence window?
+    # cadence_minutes * rate_per_minute = max tickers per cycle
+    cadence_minutes = market_cadence / 60
+    max_tickers_per_cycle = int(cadence_minutes * market_rate)
+
+    return {
+        "polygon_global_limit": POLYGON_GLOBAL_RATE_LIMIT,
+        "polygon_source_types": sorted(POLYGON_SOURCE_TYPES),
+        "per_type_limits": DEFAULT_RATE_LIMITS,
+        "cadences_seconds": DEFAULT_CADENCES,
+        "market_api": {
+            "rate_per_minute": market_rate,
+            "cadence_seconds": market_cadence,
+            "max_tickers_per_cycle": max_tickers_per_cycle,
+            "active_sources": market_count,
+        },
+        "news_api": {
+            "rate_per_minute": DEFAULT_RATE_LIMITS.get("news_api", 20),
+            "cadence_seconds": DEFAULT_CADENCES.get("news_api", 300),
+            "active_sources": news_count,
+        },
+    }
+
+
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