ppf: add periodic re-seeding of proxy source URLs

Seed sources that error out are permanently excluded from claiming.
Over time this starves the pipeline. Re-seed every 6 hours with
error reset for exhausted sources, preventing the starvation loop
that caused the previous outage.

dbs.py

@@ -639,10 +639,18 @@ PROXY_SOURCES = [
 ]
 
 
-def seed_proxy_sources(sqlite):
-    """Seed known proxy list sources into uris table."""
+def seed_proxy_sources(sqlite, reset_errors=False):
+    """Seed known proxy list sources into uris table.
+
+    Args:
+        sqlite: Database connection
+        reset_errors: If True, reset error/stale counts on existing seed
+                      sources that have errored out, allowing them to be
+                      retried. Safe to call periodically.
+    """
     timestamp = int(time.time())
     added = 0
+    reset = 0
     for url in PROXY_SOURCES:
         try:
             sqlite.execute(
@@ -653,11 +661,21 @@ def seed_proxy_sources(sqlite):
             )
             if sqlite.cursor.rowcount > 0:
                 added += 1
+            elif reset_errors:
+                # Reset errored-out seed sources so they get reclaimed
+                sqlite.execute(
+                    'UPDATE uris SET error = 0, stale_count = 0, '
+                    'check_interval = 3600, check_time = 0 '
+                    'WHERE url = ? AND error >= 5',
+                    (url,)
+                )
+                if sqlite.cursor.rowcount > 0:
+                    reset += 1
         except Exception as e:
             _log('seed_urls insert error for %s: %s' % (url, e), 'warn')
     sqlite.commit()
-    if added > 0:
-        _log('seeded %d proxy source URLs' % added, 'info')
+    if added > 0 or reset > 0:
+        _log('seed sources: %d new, %d reset' % (added, reset), 'info')
 
 
 def save_session_state(sqlite, stats):

ppf.py

@@ -1045,8 +1045,15 @@ def main():
     statusmsg = time.time()
     list_max_age_seconds = config.ppf.list_max_age_days * 86400
     last_skip_log = 0
+    last_reseed = time.time()
+    reseed_interval = 6 * 3600  # re-seed sources every 6 hours
     while True:
         try:
+            # Periodic re-seeding: reset errored-out seed sources
+            if time.time() - last_reseed >= reseed_interval:
+                dbs.seed_proxy_sources(urldb, reset_errors=True)
+                last_reseed = time.time()
+
             # When ppf threads = 0, skip URL fetching (workers handle it via /api/claim-urls)
             if config.ppf.threads == 0:
                 time.sleep(60)