fix(mcp): correct fiscal_periods column ref + remove agent auto-commit (#394)

* fix(mcp): correct fiscal_periods column ref + remove agent auto-commit

The MCP `gnubok_list_fiscal_periods` tool selected a non-existent
`fiscal_periods.status` column, causing `column fiscal_periods.status
does not exist` errors when agents called it. Fixed by selecting the
real columns (`is_closed`, `locked_at`, `closed_at`,
`opening_balances_set`) and deriving `status` in code.

Also removes the agent auto-commit feature (settings card, gating logic,
DB columns, tests). In its current shape only `create_customer` was
auto-commitable, so the toggle changed nothing meaningful in practice
while implying a level of agent autonomy that wasn't actually granted.
The risk-tier infrastructure on `pending_operations` (actor model,
risk_level) is kept since it's still used by the /pending UI filters.

Migration `20260505120000_drop_agent_auto_commit.sql` drops:
  - pending_operations.auto_commit_eligible
  - pending_operations.auto_committed_at
  - company_settings.agent_auto_commit_enabled
  - company_settings.agent_auto_commit_max_amount

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(mcp): explicitly pick fields in gnubok_list_fiscal_periods response

Greptile flagged that `...p` spreads raw DB columns (`is_closed`,
`locked_at`, `closed_at`) into the tool response alongside the
derived `status`. Drop the spread for an explicit field list so the
tool contract is the derived status only — agents don't need to
reason about raw columns, and future SELECT additions won't silently
leak.

Also drops `closed_at` from the SELECT since it wasn't read.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/helpers.ts

@@ -537,8 +537,6 @@ export function makeCompanySettings(
     onboarding_complete: true,
     sector_slug: null,
     is_sandbox: false,
-    agent_auto_commit_enabled: false,
-    agent_auto_commit_max_amount: null,
     created_at: '2024-01-01T00:00:00Z',
     updated_at: '2024-01-01T00:00:00Z',
     ...overrides,