Intermediate commit

.env.example

@@ -79,12 +79,15 @@ LOG_REDACT_FIELDS=
 SCHEDULER_ENABLED=1
 SCHEDULER_TICK_SECONDS=60
 SCHEDULER_QUEUE_BATCH_SIZE=10
+SCHEDULER_PDF_QUEUE_BATCH_SIZE=15
 INGESTION_AUTOMATION_ALLOWED=1
 INGESTION_MANUAL_RUN_ALLOWED=1
 INGESTION_MIN_RUN_INTERVAL_MINUTES=15
 INGESTION_MIN_REQUEST_DELAY_SECONDS=2
 INGESTION_NETWORK_ERROR_RETRIES=1
 INGESTION_RETRY_BACKOFF_SECONDS=1.0
+INGESTION_RATE_LIMIT_RETRIES=3
+INGESTION_RATE_LIMIT_BACKOFF_SECONDS=30.0
 INGESTION_MAX_PAGES_PER_SCHOLAR=30
 INGESTION_PAGE_SIZE=100
 INGESTION_ALERT_BLOCKED_FAILURE_THRESHOLD=1
@@ -125,6 +128,14 @@ UNPAYWALL_RETRY_COOLDOWN_SECONDS=1800
 UNPAYWALL_PDF_DISCOVERY_ENABLED=1
 UNPAYWALL_PDF_DISCOVERY_MAX_CANDIDATES=5
 UNPAYWALL_PDF_DISCOVERY_MAX_HTML_BYTES=500000
+ARXIV_ENABLED=1
+ARXIV_TIMEOUT_SECONDS=3.0
+ARXIV_MIN_INTERVAL_SECONDS=4.0
+ARXIV_RATE_LIMIT_COOLDOWN_SECONDS=60.0
+ARXIV_DEFAULT_MAX_RESULTS=3
+ARXIV_CACHE_TTL_SECONDS=900
+ARXIV_CACHE_MAX_ENTRIES=512
+ARXIV_MAILTO=
 PDF_AUTO_RETRY_INTERVAL_SECONDS=86400
 PDF_AUTO_RETRY_FIRST_INTERVAL_SECONDS=3600
 PDF_AUTO_RETRY_MAX_ATTEMPTS=3
@@ -133,6 +144,9 @@ CROSSREF_MAX_ROWS=10
 CROSSREF_TIMEOUT_SECONDS=8.0
 CROSSREF_MIN_INTERVAL_SECONDS=0.6
 CROSSREF_MAX_LOOKUPS_PER_REQUEST=8
+OPENALEX_API_KEY=
+CROSSREF_API_TOKEN=
+CROSSREF_API_MAILTO=
 
 # ------------------------------
 # Startup Bootstrap + DB Wait