chore: decommission FMP, Finnhub and Alpha Vantage (A6)

The A5 cutover has been on and observed in production, so SEC Company Facts +
DoltHub earnings are already the live source for `fundamental_data`. This
removes everything the legacy path still occupied.

Gone: the three providers and their config/env keys; the weekly
`fundamental_collector` job; the cutover toggle (SEC + Dolt is now the
unconditional path, so `off` can no longer silently freeze scoring inputs); the
A5 parity report, whose deltas became structurally zero once the candidate
builder started writing the table it compared against; and the FMP tier of
universe bootstrap.

Two behavioral notes:

- Disabling **SEC Fundamentals Import** now stops the SEC network fetch only.
  The local cache refresh moved outside the job-enable check, because candidates
  also derive from daily closes and earnings events — freezing those on an
  ingestion pause would stale scoring with no fallback left to recover from.
- `/ingestion/fetch?sources=fundamentals` still accepts the key and reports
  `skipped`; there is no per-ticker fetch any more.

Migration 029 does not blanket-delete the leftover settings rows. Migrations run
before the service restart, and pre-A6 code reads an absent `job_*_enabled` row
as *enabled* — so the two behavior-bearing keys become tombstones pinned to safe
values (hidden in Admin) and only the inert three are deleted. Removing the
provider keys from the production `.env` is the matching rollout step.

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

app/schemas/admin.py

@@ -73,11 +73,6 @@ class ActivationConfigUpdate(BaseModel):
     exclude_neutral: bool | None = None
 
 
-class FundamentalsCutoverConfigUpdate(BaseModel):
-    """Switch the legacy fundamentals cache from quota APIs to SEC/Dolt."""
-    enabled: bool
-
-
 class ScheduleConfigUpdate(BaseModel):
     """Cron schedule for the pipelines + fundamentals. Crons are 5-field
     (min hour dom month dow); timezone is an IANA name (e.g. America/New_York)."""
@@ -85,11 +80,9 @@ class ScheduleConfigUpdate(BaseModel):
     schedule_daily_pipeline_cron: str | None = Field(default=None, max_length=120)
     schedule_dolt_earnings_cron: str | None = Field(default=None, max_length=120)
     schedule_sec_fundamentals_cron: str | None = Field(default=None, max_length=120)
-    schedule_fundamentals_parity_cron: str | None = Field(default=None, max_length=120)
     schedule_near_close_pipeline_cron: str | None = Field(default=None, max_length=120)
     schedule_after_close_pipeline_cron: str | None = Field(default=None, max_length=120)
     schedule_intraday_pipeline_cron: str | None = Field(default=None, max_length=120)
-    schedule_fundamentals_cron: str | None = Field(default=None, max_length=120)
 
 
 class PerformanceConfigUpdate(BaseModel):