fix: analyst ratings timeout + add accession column to institution_filings

- Add 6s server-side timeout to Yahoo Finance quoteSummary (Promise.race) so the backend responds with stale data instead of hanging indefinitely. Stale cache is served on error (router.ts:1895-1898), matching ADR-0009.
- Hoist YahooFinance to a module-level singleton (getYf()) so the crumb/cookie is fetched once, not per call. Matches YFinanceAdapter pattern.
- Add suppressNotices for yahooSurvey to reduce log noise.
- Add accession column to institution_filings (schema.sql + migration in client.ts) and thread it through both secDataFetcher.ts INSERT paths (13D/G and 13F-HR). Fixes recurring `no such column: accession` error in new13daProducer alert tick.
- new13daProducer.ts needs no changes - its SELECT accession query now works.

app/server/src/db/client.ts

@@ -57,6 +57,7 @@ function runMigrations(db: DatabaseSync): void {
     `ALTER TABLE adapter_queue ADD COLUMN error TEXT`,
     `ALTER TABLE adapter_queue ADD COLUMN scheduled_for TEXT`,
     `ALTER TABLE insider_transactions ADD COLUMN accession TEXT`,
+    `ALTER TABLE institution_filings ADD COLUMN accession TEXT`,
     `ALTER TABLE x_credentials ADD COLUMN fred_api_key_enc TEXT`,
     `ALTER TABLE users ADD COLUMN status TEXT NOT NULL DEFAULT 'active'`,
     // Onboarding / risk posture fields added after early installs (CREATE IF NOT EXISTS does not alter).