feat: Hub-side plumbing for CFOP/IPPT write capability (flag DEFAULT OFF)

Missão 4 / Bloco E.1-E.2, on feature/cfop-ippt-write only (never main):

- Migration 0033_cfop_ippt_write_mode: Installation.cfop_ippt_write_mode
  (DISABLED|DRY_RUN|APPROVAL_REQUIRED|ENABLED, DEFAULT 'DISABLED' for every
  installation, existing and new) + append-only cfop_ippt_write_audits table.
- central/app/cfop_ippt_audit.py mirrors rtc_audit.py for this narrower
  capability: job_authorizations(installation) (delivered inside the
  authenticated job/heartbeat authorizations, never a local Agent switch) and
  record_cfop_ippt_write_audits (persists applied/aborted cells; only CFOP/
  IPPT are ever accepted, everything else silently ignored).
- central/app/web.py: POST /agents/{id}/cfop-ippt-write - ADMIN only (SSO
  Gerenciador), CSRF, typing GRAVAR required for any mode other than
  DISABLED, every change audited (CFOP_IPPT_WRITE_MODE). Small toggle UI in
  agent_detail.html next to Contexto Fiscal.
- Wired into the existing job/heartbeat authorization payload and job
  completion handling in central/app/api.py, alongside (never mixed with)
  the RTC wiring.
- 18 new tests (central/tests/test_cfop_ippt_write_plumbing.py): default
  DISABLED everywhere (job payload AND /v1/agents/me/authorizations); a
  forged completion payload can never change the mode (read fresh from the
  Installation row, never from Agent-supplied JSON); PADRAO role gets 403
  with no audit row; ADMIN + wrong/missing CSRF is refused; ADMIN without
  typing GRAVAR is refused (422); disabling never requires GRAVAR; invalid
  mode is refused; the audit recorder only accepts CFOP/IPPT, silently
  drops any other field (e.g. a stray CCLASSTRIB row).
- Two existing RTC tests updated for the additive authorizations-dict key
  (cfop_ippt_write_mode) they now also carry.

Still NOT wired into agent/scripts/run_agent_service.py::execute_job - no
Agent code calls select_candidates/apply_candidates yet, so nothing writes
to Firebird from this branch. That wiring, an Agent version bump, a new
installer and Windows Sandbox validation are the next step, deliberately
left for after review (see docs/CFOP_IPPT_WRITE_CAPABILITY_V1.md) - this
mission explicitly asked not to publish this as an active release yet.

FULL_SUITE on this branch: 1 known, expected failure -
test_manifest_records_the_real_migration_head - because this branch adds
migration 0033 that was never merged to master/deployed; RELEASE_MANIFEST.json
intentionally still describes master/production (head 0032). Every other
test passes, including all CFOP/IPPT and RTC-adjacent tests.

REAL_PRODUCT_FISCAL_WRITES=0 (no write path is reachable from any Agent
code on any branch).

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

central/tests/test_zero_touch_hub.py

@@ -280,7 +280,7 @@ def test_job_carries_the_central_rtc_authorization_default_off_and_follows_the_i
     client, engine = _client()
     hb(client)
     job = client.get("/v1/jobs/next", headers=H).json()
-    assert {k: v for k, v in job["authorizations"].items() if k != "features"} == {"rtc_write_mode": "DISABLED", "rtc_approved_codes": [], "rtc_rollbacks": []}          # never on by default
+    assert {k: v for k, v in job["authorizations"].items() if k != "features"} == {"rtc_write_mode": "DISABLED", "rtc_approved_codes": [], "rtc_rollbacks": [], "cfop_ippt_write_mode": "DISABLED"}          # never on by default
     client.post(f"/v1/jobs/{job['job_id']}/complete", json={"result_summary": {}}, headers=H)
     with Session(engine) as s:
         inst = s.scalars(select(Installation)).one()