feat!: persist T-Bank data and synchronize reads

Store account membership, portfolio, operations, forecasts and market sources in SQLite.
Coalesce scoped refreshes, fence connection revisions, preserve complete financial
snapshots and stabilize operation period state.

BREAKING CHANGE: investment reads return data/meta resource envelopes and locally
persisted snapshots; consumers must use the matching OpenAPI contract and explicit
synchronization endpoints.

src/integrations/tbank/tbank-membership.service.ts

@@ -0,0 +1,68 @@
+import { Injectable } from '@nestjs/common';
+import { randomUUID } from 'node:crypto';
+import { StructuredLogger } from '../../common/logging/structured-logger.service';
+import {
+  TbankAccessService,
+  type TbankSyncAttempt,
+} from './tbank-access.service';
+import { TbankClient } from './tbank.client';
+
+@Injectable()
+export class TbankMembershipService {
+  private readonly processRunId = randomUUID();
+  private readonly active = new Map<string, Promise<void>>();
+  private reservations: Promise<unknown> = Promise.resolve();
+
+  constructor(
+    private readonly access: TbankAccessService,
+    private readonly tbank: TbankClient,
+    private readonly logger: StructuredLogger,
+  ) {}
+
+  request(userId: string, revision: string, force = false) {
+    const reservation = this.reservations.then(async () => {
+      const requested = await this.access.reserveMembership(
+        userId,
+        revision,
+        this.processRunId,
+        new Set(this.active.keys()),
+        force,
+      );
+      if (!requested) return null;
+      const { id, attemptId } = requested.work;
+      if (requested.launch) {
+        const done = new Promise<void>((resolve) => setImmediate(resolve))
+          .then(() => this.execute({ userId, revision, id, attemptId }))
+          .catch(() =>
+            this.logger.event('error', 'tbank.membership.persistence_failed', {
+              userId,
+              code: 'TBANK_UNAVAILABLE',
+            }),
+          )
+          .finally(() => this.active.delete(attemptId));
+        this.active.set(attemptId, done);
+      }
+      return { id, done: this.active.get(attemptId) ?? Promise.resolve() };
+    });
+    this.reservations = reservation.catch(() => undefined);
+    return reservation;
+  }
+
+  private async execute(attempt: TbankSyncAttempt) {
+    try {
+      const token = await this.access.tokenForAttempt(attempt);
+      if (!token) return;
+      await this.access.publishMembership(
+        attempt,
+        await this.tbank.getOpenAccounts(token),
+        new Date(),
+        true,
+      );
+    } catch (error) {
+      await this.access.failMembership(
+        attempt,
+        error instanceof Error && error.message === 'INVALID_TBANK_TOKEN',
+      );
+    }
+  }
+}