feat(payments): chip wallet, store-compliance gate and benefit application

Stand up the internal chip/benefit mechanic behind the narrow payments interface:
context-aware balances and benefits, an atomic chip spend, admin grants as
zero-price value sales, the one-directional store-compliance gate (VK/TG same-
origin only, web draws direct→vk→tg, VK-iOS frozen, untrusted fail-closed), and
per-origin hint and no-ads application with term stacking. Reads are served from
an in-process, account-keyed write-through cache (mirroring the suspension gate),
so hot paths issue no query to the payments schema.

Flip the online-game hint wallet and the ad-banner suppression from the deprecated
accounts.hint_balance / paid_account columns to the payments benefit (a hint
balance no longer suppresses the banner — only a no-ads benefit does), and fold
chip segments and benefits by origin on account merge, inside the merge tx. Add
the GET/POST /api/v1/user/wallet edge chain (REST → Connect → FlatBuffers) plus
its codec unit test; no wallet UI yet.

Bring the frozen owner decisions log into the repo at
docs/PAYMENTS_DECISIONS_ru.md (it was untracked under .vscode) and reference it
from PLAN.md; record the read-cache design and the present-sources interface in
PLAN.md and docs/PAYMENTS.md (+ RU mirror).

ui/src/gen/fbs/scrabblefb.ts

@@ -81,5 +81,8 @@ export { TelegramLoginRequest } from './scrabblefb/telegram-login-request.js';
 export { TileRecord } from './scrabblefb/tile-record.js';
 export { UpdateProfileRequest } from './scrabblefb/update-profile-request.js';
 export { VKLoginRequest } from './scrabblefb/vklogin-request.js';
+export { Wallet } from './scrabblefb/wallet.js';
+export { WalletBuyRequest } from './scrabblefb/wallet-buy-request.js';
+export { WalletSegment } from './scrabblefb/wallet-segment.js';
 export { WordCheckResult } from './scrabblefb/word-check-result.js';
 export { YourTurnEvent } from './scrabblefb/your-turn-event.js';

ui/src/gen/fbs/scrabblefb/wallet-buy-request.ts

@@ -0,0 +1,48 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+import * as flatbuffers from 'flatbuffers';
+
+export class WalletBuyRequest {
+  bb: flatbuffers.ByteBuffer|null = null;
+  bb_pos = 0;
+  __init(i:number, bb:flatbuffers.ByteBuffer):WalletBuyRequest {
+  this.bb_pos = i;
+  this.bb = bb;
+  return this;
+}
+
+static getRootAsWalletBuyRequest(bb:flatbuffers.ByteBuffer, obj?:WalletBuyRequest):WalletBuyRequest {
+  return (obj || new WalletBuyRequest()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+static getSizePrefixedRootAsWalletBuyRequest(bb:flatbuffers.ByteBuffer, obj?:WalletBuyRequest):WalletBuyRequest {
+  bb.setPosition(bb.position() + flatbuffers.SIZE_PREFIX_LENGTH);
+  return (obj || new WalletBuyRequest()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+productId():string|null
+productId(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+productId(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 4);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
+static startWalletBuyRequest(builder:flatbuffers.Builder) {
+  builder.startObject(1);
+}
+
+static addProductId(builder:flatbuffers.Builder, productIdOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(0, productIdOffset, 0);
+}
+
+static endWalletBuyRequest(builder:flatbuffers.Builder):flatbuffers.Offset {
+  const offset = builder.endObject();
+  return offset;
+}
+
+static createWalletBuyRequest(builder:flatbuffers.Builder, productIdOffset:flatbuffers.Offset):flatbuffers.Offset {
+  WalletBuyRequest.startWalletBuyRequest(builder);
+  WalletBuyRequest.addProductId(builder, productIdOffset);
+  return WalletBuyRequest.endWalletBuyRequest(builder);
+}
+}

ui/src/gen/fbs/scrabblefb/wallet-segment.ts

@@ -0,0 +1,68 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+import * as flatbuffers from 'flatbuffers';
+
+export class WalletSegment {
+  bb: flatbuffers.ByteBuffer|null = null;
+  bb_pos = 0;
+  __init(i:number, bb:flatbuffers.ByteBuffer):WalletSegment {
+  this.bb_pos = i;
+  this.bb = bb;
+  return this;
+}
+
+static getRootAsWalletSegment(bb:flatbuffers.ByteBuffer, obj?:WalletSegment):WalletSegment {
+  return (obj || new WalletSegment()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+static getSizePrefixedRootAsWalletSegment(bb:flatbuffers.ByteBuffer, obj?:WalletSegment):WalletSegment {
+  bb.setPosition(bb.position() + flatbuffers.SIZE_PREFIX_LENGTH);
+  return (obj || new WalletSegment()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+source():string|null
+source(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+source(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 4);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
+chips():number {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
+spendable():boolean {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? !!this.bb!.readInt8(this.bb_pos + offset) : false;
+}
+
+static startWalletSegment(builder:flatbuffers.Builder) {
+  builder.startObject(3);
+}
+
+static addSource(builder:flatbuffers.Builder, sourceOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(0, sourceOffset, 0);
+}
+
+static addChips(builder:flatbuffers.Builder, chips:number) {
+  builder.addFieldInt32(1, chips, 0);
+}
+
+static addSpendable(builder:flatbuffers.Builder, spendable:boolean) {
+  builder.addFieldInt8(2, +spendable, +false);
+}
+
+static endWalletSegment(builder:flatbuffers.Builder):flatbuffers.Offset {
+  const offset = builder.endObject();
+  return offset;
+}
+
+static createWalletSegment(builder:flatbuffers.Builder, sourceOffset:flatbuffers.Offset, chips:number, spendable:boolean):flatbuffers.Offset {
+  WalletSegment.startWalletSegment(builder);
+  WalletSegment.addSource(builder, sourceOffset);
+  WalletSegment.addChips(builder, chips);
+  WalletSegment.addSpendable(builder, spendable);
+  return WalletSegment.endWalletSegment(builder);
+}
+}

ui/src/gen/fbs/scrabblefb/wallet.ts

@@ -0,0 +1,96 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+import * as flatbuffers from 'flatbuffers';
+
+import { WalletSegment } from '../scrabblefb/wallet-segment.js';
+
+
+export class Wallet {
+  bb: flatbuffers.ByteBuffer|null = null;
+  bb_pos = 0;
+  __init(i:number, bb:flatbuffers.ByteBuffer):Wallet {
+  this.bb_pos = i;
+  this.bb = bb;
+  return this;
+}
+
+static getRootAsWallet(bb:flatbuffers.ByteBuffer, obj?:Wallet):Wallet {
+  return (obj || new Wallet()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+static getSizePrefixedRootAsWallet(bb:flatbuffers.ByteBuffer, obj?:Wallet):Wallet {
+  bb.setPosition(bb.position() + flatbuffers.SIZE_PREFIX_LENGTH);
+  return (obj || new Wallet()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+segments(index: number, obj?:WalletSegment):WalletSegment|null {
+  const offset = this.bb!.__offset(this.bb_pos, 4);
+  return offset ? (obj || new WalletSegment()).__init(this.bb!.__indirect(this.bb!.__vector(this.bb_pos + offset) + index * 4), this.bb!) : null;
+}
+
+segmentsLength():number {
+  const offset = this.bb!.__offset(this.bb_pos, 4);
+  return offset ? this.bb!.__vector_len(this.bb_pos + offset) : 0;
+}
+
+adsForever():boolean {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? !!this.bb!.readInt8(this.bb_pos + offset) : false;
+}
+
+adsPaidUntilMs():bigint {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? this.bb!.readInt64(this.bb_pos + offset) : BigInt('0');
+}
+
+hints():number {
+  const offset = this.bb!.__offset(this.bb_pos, 10);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
+static startWallet(builder:flatbuffers.Builder) {
+  builder.startObject(4);
+}
+
+static addSegments(builder:flatbuffers.Builder, segmentsOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(0, segmentsOffset, 0);
+}
+
+static createSegmentsVector(builder:flatbuffers.Builder, data:flatbuffers.Offset[]):flatbuffers.Offset {
+  builder.startVector(4, data.length, 4);
+  for (let i = data.length - 1; i >= 0; i--) {
+    builder.addOffset(data[i]!);
+  }
+  return builder.endVector();
+}
+
+static startSegmentsVector(builder:flatbuffers.Builder, numElems:number) {
+  builder.startVector(4, numElems, 4);
+}
+
+static addAdsForever(builder:flatbuffers.Builder, adsForever:boolean) {
+  builder.addFieldInt8(1, +adsForever, +false);
+}
+
+static addAdsPaidUntilMs(builder:flatbuffers.Builder, adsPaidUntilMs:bigint) {
+  builder.addFieldInt64(2, adsPaidUntilMs, BigInt('0'));
+}
+
+static addHints(builder:flatbuffers.Builder, hints:number) {
+  builder.addFieldInt32(3, hints, 0);
+}
+
+static endWallet(builder:flatbuffers.Builder):flatbuffers.Offset {
+  const offset = builder.endObject();
+  return offset;
+}
+
+static createWallet(builder:flatbuffers.Builder, segmentsOffset:flatbuffers.Offset, adsForever:boolean, adsPaidUntilMs:bigint, hints:number):flatbuffers.Offset {
+  Wallet.startWallet(builder);
+  Wallet.addSegments(builder, segmentsOffset);
+  Wallet.addAdsForever(builder, adsForever);
+  Wallet.addAdsPaidUntilMs(builder, adsPaidUntilMs);
+  Wallet.addHints(builder, hints);
+  return Wallet.endWallet(builder);
+}
+}