chore: drop the A6 rollback tombstones

A6 deployed cleanly and the provider keys are gone from the production `.env`,
which makes the legacy collector inert regardless of any settings row. The two
tombstones migration 029 pinned have no remaining job, and nothing in the
codebase reads either key.

Migration 030 deletes them and drops the Admin filter that hid them. Unlike
029's, its downgrade is meaningful — it restores both rows at their safe values,
since going back past this revision means going back toward code that reads them.

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

docs/dolt-integration-plan.md

@@ -432,9 +432,10 @@ workstream B — Alpaca remains the price source throughout.
   remaining production action is flipping that switch on and observing it.
 - A6. **DONE 2026-08-07.** FMP/Finnhub/Alpha Vantage removed, along with the
   weekly `fundamental_collector` job, the A5 cutover toggle (SEC+Dolt is now the
-  unconditional path) and the parity report. Migration `029` tombstones the two
-  behavior-bearing settings rows for the rollback window; the archived parity
-  bundles stay as the A5 evidence trail.
+  unconditional path) and the parity report. Migration `029` tombstoned the two
+  behavior-bearing settings rows for the rollback window and `030` dropped them
+  once the deploy was confirmed healthy; the archived parity bundles stay as the
+  A5 evidence trail.
 
 **Workstream B (independent, start when wanted):**
 
@@ -514,8 +515,8 @@ observed in production, so the legacy providers, their config/env keys, the week
 collector job and the parity report were all removed. Two consequences to carry:
 (1) `fundamental_data` now has no provider fallback — recovery is restore-from-backup;
 (2) disabling **SEC Fundamentals Import** stops the SEC fetch only, because the local
-cache refresh was deliberately moved outside the job-enable check. Remaining
-follow-up: delete the migration-029 tombstone rows once the rollback window closes.
+cache refresh was deliberately moved outside the job-enable check. No follow-ups
+remain: migration `030` dropped the tombstone rows after the deploy was verified.
 
 **Known caveats to carry (documented in the findings report, not bugs to fix):**
 - KLAC-class post-filing splits: P/E wrong until the next 10-Q; undetectable from