feat(dolt): A2 — DoltHub earnings importer (shadow ingestion)

A SourceImporter that ingests post-no-preference/earnings into earnings_events
for the tracked universe. Shadow by construction (nothing reads earnings_events
until A4).

- earnings_alignment.py: pure calendar<->EPS-history min-cost monotonic DP,
  reused from scripts/import_dolthub_earnings.py with identical constants (not
  extending that one-off script); symbol/session normalization; unit-tested
  against the pinned constants.
- dolt_client.py: async dolt CLI wrapper (pull / current_commit / query_csv via
  asyncio.create_subprocess_exec — never blocks the shared event loop) + disk
  guard before pull.
- dolt_earnings_importer.py: detect_revision = pull + HEAD hash; stage = query
  earnings_calendar + eps_history, dedup, align, map act_symbol->ticker_id
  (normalize both sides so dotted BRK.B joins); promote is destructive
  (delete future dolt_earnings rows + upsert; past never deleted) so validate is
  FAIL-CLOSED — blocks when the staged forward calendar is empty or has collapsed
  below 50% of what's loaded (the forward calendar is the acceptance gate).
- NOTICE: CC BY-SA 4.0 attribution; config: DOLT_BINARY / DOLT_DATA_DIR / etc.

Verified end-to-end against the real 1.68 GB clone (5 tickers: 133 events, 128
paired, forward calendar to 2026-08-26, BRK.B joined). Tests: 9 alignment + 7
importer + 1 skip-guarded real-clone smoke. Full suite 699 passed.

Remaining for A2: wire the daily ~02:30 ET shadow cron — deferred to pair with
the deploy-time dolt install + DOLT_DATA_DIR provisioning.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/config.py

@@ -37,6 +37,16 @@ class Settings(BaseSettings):
     # Fundamentals Provider — Alpha Vantage (optional fallback)
     alpha_vantage_api_key: str = ""
 
+    # Dolt bulk-data — local clone of post-no-preference/earnings (workstream A).
+    # dolt_binary: full path when not on PATH (dev/Windows install). dolt_data_dir
+    # holds the clones; in production it MUST be outside the deploy tree (deploy is
+    # rsync --delete) — set DOLT_DATA_DIR to a persistent path. The earnings clone
+    # lives at <dolt_data_dir>/<dolt_earnings_subdir>.
+    dolt_binary: str = "dolt"
+    dolt_data_dir: str = "dolt-data"
+    dolt_earnings_subdir: str = "earnings"
+    dolt_min_free_disk_gb: float = 2.0
+
     # Regime Monitor — FRED (VIX level + HY credit spreads). Optional: without it
     # the volatility (P5) and credit-spread (F2) signals are reported as n/a.
     fred_api_key: str = ""