fix(sports): recover from ESPN rejecting scoreboard date ranges (#591)

* fix(sports): recover from ESPN rejecting scoreboard date ranges

Since 2026-09-15 ESPN's site API answers `dates=YYYYMMDD-YYYYMMDD` with
400 "Failed to get events endpoint." for every sport. Single days, months
(`YYYYMM`) and season years still work. Every season and weeks-window fetch
in core failed, including the background service the scoreboards submit
their season schedules to.

src/common/espn_dates.py re-asks a rejected range as whole-month chunks
plus the leftover edge days, which tile the window exactly (a season is
8 requests, not 213). A month that comes back with exactly 500 events is
truncated (college baseball's March) and is re-asked day by day.

It also clamps `limit` to 500: above that ESPN truncates silently, e.g.
college football returns 25 of 68 games for one Saturday at limit=1000.

BackgroundDataService recovers rejected ranges on the worker thread and
advertises `handles_espn_date_ranges` so plugins can tell whether to hand
it a range. SportsCore, sports_shared, ESPNDataSource and APIHelper route
through the helper or the clamped limit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* docs(changelog): ESPN date-range fallback and limit clamp

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(sports): stop re-sending ESPN date ranges once one is rejected

Live scoreboards refresh every 30 seconds, and each refresh sent the range
first, got the 400, then fetched the chunks: three requests where one used
to do. After a rejection, ranges now go straight to chunks for six hours,
then the range is tried again so the workaround retires itself if ESPN
reverts. A single-day 400 does not set the memo, and when every chunk fails
the range request supplies the error without the chunks being fetched a
second time. Per-fetch chunk logging drops to debug; the rejection itself
stays a warning.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(sports): clamp limit only on ESPN scoreboard submissions

The background service is generic, and limit above 500 only truncates
scoreboards. /teams needs limit=1000 (college football has 762 teams and
limit=500 returns 500), so a teams submission must keep its limit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

src/common/api_helper.py

@@ -8,6 +8,7 @@ Extracted from LEDMatrix core to provide reusable functionality for plugins.
 import logging
 import time
 from datetime import datetime
+from src.common.espn_dates import ESPN_MAX_LIMIT
 from typing import Any, Dict, Optional
 
 import requests
@@ -153,9 +154,11 @@ class APIHelper:
             cache_key = f"espn_{sport}_{league}_{date}"
         
         # Set parameters
+        # limit above 500 makes ESPN truncate instead of erroring: college
+        # football came back with 25 of 68 games. See src/common/espn_dates.py.
         params = {
             'dates': date,
-            'limit': 1000
+            'limit': ESPN_MAX_LIMIT
         }
         
         return self.get(url, params=params, cache_key=cache_key, cache_ttl=cache_ttl)