feat(payments): per-channel Robokassa shops on the direct rail

Split the single Robokassa direct rail into one merchant shop per channel
(web / android; ios later), chosen by the trusted X-Platform subtype, while
every shop still credits the one `direct` wallet — merchant-account separation
for accounting and receipts, not a new wallet.

- config: a channel-keyed shops registry (web seeds from the legacy vars or
  _WEB_*, android from _ANDROID_*); an empty shop leaves the rail dormant;
  per-shop validation.
- intake: the order picks its shop by subtype (unknown falls back to web); the
  per-shop Result callback is verified by that shop's own Password2 at
  /pay/robokassa/result/<channel> (the gateway extracts the channel; Caddy's
  /pay/* glob already forwards it — no Caddyfile change).
- persistence: an additive `shop` column on the order (migration 00015),
  recorded from the payment context, surfaced per entry in the admin report.
- standalone apps sign in by email only, so a direct purchase keeps its email
  anchor.
- docs: PAYMENTS (+ru) topology, deploy env vars + compose mapping, the
  decisions log (D41 revised for the ИП / 54-ФЗ move; D42-D44), the plan.

Contour-safe: dormant until shops are configured; the migration is additive
(no wipe); no client wire change. Fiscalization (Receipt/Email) and the gateway
`direct/android` subtype follow when the ИП / RuStore are live.

PLAN.md

@@ -39,10 +39,12 @@ status — without re-deriving decisions.
 | E7 | Admin, reports & catalog | 2 | DONE |
 | E8 | Guest limits | — | DONE |
 | E9 | Tournament fee | future | TODO |
+| E10 | Multi-shop direct rail + ИП fiscalization | 2+ | TODO |
 
 **Release 1** = full mechanics with no real money, exercised via `admin_grant` (E0→E1→E2→E3).
 **Release 2** = money (E4→E5→E6→E7). E8 is standalone (game-behaviour change, can run in
-parallel). E9 is future.
+parallel). E9 is future. E10 splits the `direct` rail into per-channel Robokassa shops + ИП
+fiscalization (post-launch, backend-first).
 
 ---
 
@@ -892,6 +894,92 @@ tournament-entry storage + pricing design.
 
 ---
 
+## E10 — Multi-shop direct rail + ИП fiscalization
+
+**Status:** TODO · **Release 2+ (post-launch, backend-first)** · depends on: E5 (intake/`Fund`,
+the `robokassa` adapter, the Result callback), E7 (the per-user report — channel breakdown) ·
+mechanics: PAYMENTS §9, §12; decisions D41 (rev), D42–D44.
+
+**Goal.** Split the single Robokassa `direct` rail into **per-channel merchant shops** (web,
+android; ios later) — separate merchant accounts / withdrawal / accounting and a per-channel
+breakdown in the E7 report — while keeping **one `direct` wallet** (D42). Land the wallet/identity
+rules the native apps need (email-only anchor, D43) and revise fiscalization for the owner's move
+to **ИП / 54-ФЗ** (D41 rev). All **additive / contour-safe** and **money-live** → expand-contract
+throughout.
+
+**Locked decisions (owner interview 2026-07-14): D41 (rev), D42, D43, D44.** No wallet-model /
+spend-wall change; the split is merchant-account routing under one `direct` segment. Route the shop
+by the **trusted** `X-Platform` subtype, never a client field; unknown → `web`.
+
+**B1 — Config: one shop → a set of shops.**
+
+- `robokassa.Config` (single) → a **shops registry** keyed by channel (`web`, `android`; `ios`
+  later), each 4 fields (`MerchantLogin`/`Password1`/`Password2`/`IsTest`). New env
+  `BACKEND_ROBOKASSA_WEB_*`, `BACKEND_ROBOKASSA_ANDROID_*`.
+- **Expand-contract, no flag-day:** the legacy `BACKEND_ROBOKASSA_*` seeds the `web` shop; add the
+  new vars; retire the legacy set after the prod rollout sets the split vars. `validate()`: a shop
+  with a login must carry both passwords (mirror the current check), per shop.
+- Config/README + `deploy/.env.example` + the deploy ansible vars.
+
+**B2 — Route the shop by channel (intake).**
+
+- `handleWalletOrder` `SourceDirect` branch: pick the shop by `cxt.Subtype` (`web`/`android`;
+  unknown → `web`). Build the payment request from that shop. The subtype rides the trusted
+  gateway-injected `X-Platform` (`<kind>/<subtype>`, `parsePlatformHeader`) — no spoofable client
+  field. **Verify the gateway emits `direct/android` for the native build**; if it sends a bare
+  `direct/`, add the android subtype (small gateway change).
+- Record the chosen `shop` on the order (feeds B5).
+
+**B3 — Per-shop Result callbacks.**
+
+- The callback must select the right `Password2` → each shop gets its own Result URL:
+  **per-shop public edge routes** (mirror the existing single Robokassa Result route, e.g.
+  `…/result/web`, `…/result/android`), each forwarded to the backend and verified with that shop's
+  config, then the same `Fund` (source stays `direct`). Add the routes to the **Caddyfile
+  `@gateway` matcher** (else they fall to the landing catch-all) **+ a CI probe per route**.
+- Keep the legacy single route alive (shop = `web`) through the expand-contract window until the
+  cabinet Result URLs are cut over.
+
+**B4 — ИП fiscalization (D41 rev) — orthogonal, gated on the owner's ИП/ОФД/СНО.**
+
+- **Owner/cabinet:** enable the 54-ФЗ cloud kassa in the Robokassa ЛКК (kassa + ОФД + СНО).
+  Required for ИП regardless of code.
+- **Code (optional, itemized чеки):** send a one-line `Receipt` (pack name, qty 1, `sum`, `tax`
+  per СНО, `payment_object`/`payment_method`) + the customer `Email` (the D36 confirmed anchor) in
+  the payment request; extend the signature to `MerchantLogin:OutSum:InvId:Receipt:Password1`
+  (URL-encode `Receipt`). One line fits the current GET redirect; POST-form only as a URL-length
+  fallback. One feature, all shops. **Sequenced last** — the split (B1–B3, B5, B6) needs no
+  fiscalization. Supersedes the E5 §12 shop-side НПД receipt note.
+
+**B5 — Channel in the report (D44).**
+
+- Additive `shop` column on the order (default `web` / backfill from `origin`); a per-channel
+  breakdown in the E7 per-user report (D40). Expand-contract migration (nullable/defaulted column),
+  **contour-safe** (a schema touch → note the contour `DROP SCHEMA` step in `PRERELEASE.md`).
+
+**B6 — Tests + docs.**
+
+- unit: the `robokassa` shops registry + per-shop `VerifyResult` (right `Password2`);
+  signature-with-`Receipt` (B4); intake shop routing by subtype (web/android/unknown→web).
+- integration: order→per-shop callback→credit (each route), a duplicate credits once, an expired
+  order still honoured; the `shop` recorded + reported.
+- docs: `PAYMENTS.md` (+`_ru`) the multi-shop topology + the ИП/54-ФЗ receipt revision;
+  `deploy/README` + `.env.example` the new vars + the per-shop Result routes + probes;
+  `PRERELEASE.md` the `shop` column contour step.
+
+**Done-criteria.** A `direct/web` order pays through the web shop and `direct/android` through the
+android shop, each verified with its own `Password2`, both crediting one `direct` wallet exactly
+once; the E7 report breaks payments down by channel; the split stays contour-safe (the legacy shop
+still works until the cabinet cutover). B4 (fiscalization) verified when the owner's ИП/ОФД/СНО are
+live.
+
+**Notes/risks.** Edge routes fall through if not in the Caddyfile `@gateway` matcher — add a CI
+probe (field note). The prod rolling deploy skips caddy on config-only changes — force-recreate on a
+Caddyfile change. Money-live: expand-contract only, image rollback DB-safe. Confirm the gateway
+emits `direct/android` for the native build before relying on subtype routing.
+
+---
+
 ## Verification & CI (all stages)
 
 - Per-stage tests at the layers above; **compliance-gate regression is mandatory** (a