feat(amendment): soccorso istruttorio v3 — base dati + endpoint CRUD + internal BE

ROUND 1 della replica soccorso istruttorio speculare al BE Gepafin
bflows-bandi-be. Pacchetto base pronto, mancano scheduler/upload/email/FE
che vengono in round successivi.

==ARCHITETTURA DECISA CON CARLO==
- multi-tenancy lato BE: microservizio resta tenant-agnostic
- BE (bflows-bandi-be) fa polling sul nostro /internal e invia PEC/protocollo
  tenant-aware (hub=1 Gepafin PEC_SERVICE, hub=2 SviluppUmbria MAILGUN_SERVICE)
- microservizio NON fa PEC ne protocollo, NON conosce hub_id
- endpoint interni autenticati via shared secret X-Internal-Secret

==MIGRATION DB (2)==
mig 7: ALTER TABLE remission_amendment_request ADD
  response_days, extended_days, extension_date, internal_note,
  amendment_document_path/type, amendment_initial_document_path,
  response_document_path/type, protocol_id, email_log_id, user_action_id,
  pec_sent_at, pec_failed_reason, pec_retry_after
  + 2 index partial (status pec-pending, deadline scadenti)

mig 8: nuova tabella remission_expiration_config (type, interval_days,
  is_deleted) per reminder data-driven speculare a expiration_config BE.
  Seeded con (AMENDMENT, 7) e (AMENDMENT, 2).

==MODELLI==
- RemissionAmendmentRequest esteso con 13 colonne nuove
- RemissionExpirationConfig nuovo

==SCHEMAS==
- AmendmentStatus enum (DRAFT, AWAITING, RESPONSE_RECEIVED, EXPIRED, CLOSED)
- AmendmentRequestCreate esteso (response_days, internal_note)
- AmendmentRequestUpdate nuovo (solo DRAFT)
- AmendmentExtend nuovo (proroga)
- AmendmentPendingPecOut, AmendmentPecDetail (per BE polling)
- MarkPecSent, MarkPecFailed (callback BE)

==ENDPOINT ISTRUTTORE (estesi o nuovi)==
- POST /{pid}/amendment              crea DRAFT (modifica: non piu AWAITING diretto)
- PUT  /{pid}/amendment/{id}         modifica solo DRAFT [NUOVO]
- DELETE /{pid}/amendment/{id}       elimina solo DRAFT [NUOVO]
- POST /{pid}/amendment/{id}/send    DRAFT -> AWAITING [NUOVO]
- POST /{pid}/amendment/{id}/extend  proroga deadline [NUOVO]
- POST /{pid}/amendment/{id}/reminder reminder manuale (flag pec_retry_after) [NUOVO]
- POST /{pid}/amendment/{id}/close   chiude (AmendmentStatus enum al posto di stringhe)
- POST /{pid}/amendment/{id}/respond-beneficiary  benef risponde

==ENDPOINT INTERNI /internal/remission-amendments (nuovi)==
- GET     ?status=pending-pec|pending-reminder&since=
- GET     /{id}                        detail per composizione PEC
- POST    /{id}/mark-pec-sent          callback BE success
- POST    /{id}/mark-pec-failed        callback BE failure
Auth: X-Internal-Secret header, 401 altrimenti.

==CONFIG==
RENDIC_INTERNAL_SECRET env var (default sandbox hard-coded).

==TEST E2E==
/tmp/test_amendment_v3.py - 10 step tutti verdi:
  A reset T2 UNDER_REVIEW
  B create DRAFT (response_days=15 default)
  C update DRAFT (response_days=20, internal_note)
  D send DRAFT->AWAITING, pratica AWAITING_AMENDMENT
  E BE poll pending-pec vede amendment
  F BE detail+mark-pec-sent salva protocol_id/email_log_id/user_action_id
  G dopo mark-pec-sent scompare da pending-pec
  H benef respond -> RESPONSE_RECEIVED
  I istruttore close -> CLOSED, pratica torna UNDER_REVIEW
  AUTH internal senza secret -> 401

==NEXT (non in questo commit)==
- scheduler APScheduler cron 01:00 EXPIRED + cron 09:00 reminder
- upload amendment_document (istruttore) + response_document (benef) via files router
- template email locali non-PEC (reminder istruttore, notifica chiusura)
- UI istruttore: lista amendment + form crea/invia + proroga + reminder manuale
- UI benef: vista amendment + risposta con upload

app/migrations.py

@@ -106,6 +106,59 @@ MIGRATIONS = [
     CREATE INDEX IF NOT EXISTS idx_custom_check_practice
         ON gepafin_rendic.remission_custom_check_value(practice_id);
     """,
+    # 2026-04-20 v3: soccorso istruttorio speculare al BE Gepafin
+    # - stato DRAFT (istruttore prepara, non ancora inviato)
+    # - response_days + extended_days + extension_date (prolunghe)
+    # - internal_note (visibile solo istruttore, separata da request_text)
+    # - amendment_document_* (allegato istruttore al soccorso, firmato e no)
+    # - response_document_* (upload risposta beneficiario)
+    # - protocol_id + email_log_id + user_action_id (popolati dal BE via mark-pec-sent)
+    # - pec_sent_at + pec_failed_reason + pec_retry_after (tracking PEC asincrono)
+    # Lato microservizio NON gestiamo PEC ne protocollo: il BE multi-tenant
+    # (gepafin_schema.hub id=1 PEC_SERVICE, id=2 MAILGUN_SERVICE) fa polling
+    # su endpoint /internal/remission-amendments e notifica via mark-pec-sent/failed.
+    """
+    ALTER TABLE gepafin_rendic.remission_amendment_request
+        ADD COLUMN IF NOT EXISTS response_days integer,
+        ADD COLUMN IF NOT EXISTS extended_days integer,
+        ADD COLUMN IF NOT EXISTS extension_date timestamptz,
+        ADD COLUMN IF NOT EXISTS internal_note text,
+        ADD COLUMN IF NOT EXISTS amendment_document_path varchar(1024),
+        ADD COLUMN IF NOT EXISTS amendment_document_type varchar(128),
+        ADD COLUMN IF NOT EXISTS amendment_initial_document_path varchar(1024),
+        ADD COLUMN IF NOT EXISTS response_document_path varchar(1024),
+        ADD COLUMN IF NOT EXISTS response_document_type varchar(128),
+        ADD COLUMN IF NOT EXISTS protocol_id varchar(128),
+        ADD COLUMN IF NOT EXISTS email_log_id integer,
+        ADD COLUMN IF NOT EXISTS user_action_id integer,
+        ADD COLUMN IF NOT EXISTS pec_sent_at timestamptz,
+        ADD COLUMN IF NOT EXISTS pec_failed_reason text,
+        ADD COLUMN IF NOT EXISTS pec_retry_after timestamptz;
+    CREATE INDEX IF NOT EXISTS idx_amendment_status_pec
+        ON gepafin_rendic.remission_amendment_request(status)
+        WHERE status IN ('DRAFT','AWAITING');
+    CREATE INDEX IF NOT EXISTS idx_amendment_deadline
+        ON gepafin_rendic.remission_amendment_request(deadline)
+        WHERE status = 'AWAITING';
+    """,
+    # 2026-04-20 v4: tabella config reminder data-driven, speculare al BE
+    # (expiration_config type='AMENDMENT' interval_days=N). Permette righe multiple
+    # per triggerare reminder a N gg diversi dalla scadenza (es. 7gg + 2gg).
+    """
+    CREATE TABLE IF NOT EXISTS gepafin_rendic.remission_expiration_config (
+        id serial PRIMARY KEY,
+        type varchar(50) NOT NULL,
+        interval_days integer NOT NULL CHECK (interval_days > 0),
+        is_deleted boolean NOT NULL DEFAULT false,
+        created_at timestamptz NOT NULL DEFAULT NOW()
+    );
+    CREATE INDEX IF NOT EXISTS idx_expiration_config_type
+        ON gepafin_rendic.remission_expiration_config(type)
+        WHERE is_deleted = false;
+    INSERT INTO gepafin_rendic.remission_expiration_config (type, interval_days)
+    VALUES ('AMENDMENT', 7), ('AMENDMENT', 2)
+    ON CONFLICT DO NOTHING;
+    """,
 ]