refactor(server): drop redis stream + worker role (#1792)

The Redis Stream `billing-events` + `worker` Railway role +
advisory-lock poller layered together didn't actually buy us reliability
— `debitFlux` swallowed XADD failures, leaving the door open to "balance
updated, ledger row never written". Collapse the whole thing back to:
`creditFlux` and `debitFlux` write `flux_transaction` ledger rows inline
within the same DB transaction that mutates `user_flux`, and `(user_id,
request_id)` remains the partial unique index that keeps retries safe.

Concrete changes:
- Inline ledger inserts in `BillingService.{debitFlux, creditFlux,
creditFluxFromStripeCheckout, creditFluxFromInvoice}`; drop `billingMq`
and `publishEvent` plumbing entirely.
- `routes/openai/v1` writes `llm_request_log` synchronously via the
existing `requestLogService`; the duplicate `llm-request-log.ts` service
module is removed.
- `bin/run-worker.ts`, `libs/mq/*`,
`services/billing/billing-events.ts`,
`services/billing/billing-consumer-handler.ts`, and matching tests are
deleted. CLI now exposes only `api`.
- `BILLING_EVENTS_*` env vars and the `DEFAULT_BILLING_EVENTS_STREAM`
helper are dropped; `docker-compose.yml` no longer ships a worker
service.
- `docs/ai-context/{workers-and-runtime, billing-architecture,
redis-boundaries-and-pubsub, data-model-and-state,
architecture-overview, README}.md`, `CLAUDE.md`, and the existing
verification docs are updated to describe the single-process synchronous
pipeline.

Tests: 29 files / 247 cases pass. Production deployments need to drop
the worker Railway service after this lands.

apps/server/src/app.ts

@@ -3,10 +3,8 @@ import type Redis from 'ioredis'
 import type { AuthInstance } from './libs/auth'
 import type { Database } from './libs/db'
 import type { Env } from './libs/env'
-import type { MqService } from './libs/mq'
 import type { OtelInstance } from './libs/otel'
-import type { FluxGrantBatchService } from './services/admin-flux-grant-batch/flux-grant-batch-service'
-import type { BillingEvent } from './services/billing/billing-events'
+import type { AdminFluxGrantsService } from './services/admin-flux-grants'
 import type { BillingService } from './services/billing/billing-service'
 import type { FluxMeter } from './services/billing/flux-meter'
 import type { CharacterService } from './services/characters'
@@ -15,6 +13,7 @@ import type { ConfigKVService } from './services/config-kv'
 import type { FluxService } from './services/flux'
 import type { FluxTransactionService } from './services/flux-transaction'
 import type { ProviderService } from './services/providers'
+import type { RequestLogService } from './services/request-log'
 import type { StripeService } from './services/stripe'
 import type { UserDeletionService } from './services/user-deletion'
 import type { HonoEnv } from './types/hono'
@@ -41,7 +40,7 @@ import { createRedis } from './libs/redis'
 import { resolveRequestAuth } from './libs/request-auth'
 import { sessionMiddleware } from './middlewares/auth'
 import { otelMiddleware } from './middlewares/otel'
-import { createAdminFluxGrantBatchRoutes } from './routes/admin/flux-grant-batches'
+import { createAdminFluxGrantsRoutes } from './routes/admin/flux-grants'
 import { createAuthRoutes } from './routes/auth'
 import { createCharacterRoutes } from './routes/characters'
 import { createChatWsHandlers } from './routes/chat-ws'
@@ -50,8 +49,7 @@ import { createFluxRoutes } from './routes/flux'
 import { createV1CompletionsRoutes } from './routes/openai/v1'
 import { createProviderRoutes } from './routes/providers'
 import { createStripeRoutes } from './routes/stripe'
-import { createFluxGrantBatchService } from './services/admin-flux-grant-batch/flux-grant-batch-service'
-import { createBillingMq } from './services/billing/billing-events'
+import { createAdminFluxGrantsService } from './services/admin-flux-grants'
 import { createBillingService } from './services/billing/billing-service'
 import { createFluxMeter } from './services/billing/flux-meter'
 import { createCharacterService } from './services/characters'
@@ -78,9 +76,9 @@ interface AppDeps {
   fluxTransactionService: FluxTransactionService
   stripeService: StripeService
   billingService: BillingService
-  fluxGrantBatchService: FluxGrantBatchService
+  adminFluxGrantsService: AdminFluxGrantsService
   ttsMeter: FluxMeter
-  billingMq: MqService<BillingEvent>
+  requestLogService: RequestLogService
   configKV: ConfigKVService
   redis: Redis
   env: Env
@@ -213,7 +211,7 @@ export async function buildApp(deps: AppDeps) {
     /**
      * V1 routes for official provider.
      */
-    .route('/api/v1/openai', createV1CompletionsRoutes(deps.fluxService, deps.billingService, deps.configKV, deps.billingMq, deps.ttsMeter, deps.redis, deps.env, deps.otel?.genAi))
+    .route('/api/v1/openai', createV1CompletionsRoutes(deps.fluxService, deps.billingService, deps.configKV, deps.requestLogService, deps.ttsMeter, deps.redis, deps.env, deps.otel?.genAi))
 
     /**
      * Flux routes.
@@ -226,10 +224,10 @@ export async function buildApp(deps: AppDeps) {
     .route('/api/v1/stripe', createStripeRoutes(deps.fluxService, deps.stripeService, deps.billingService, deps.configKV, deps.env, deps.redis, deps.otel?.revenue))
 
     /**
-     * Admin routes — guarded by ADMIN_USER_IDS allowlist. v1 only includes
-     * batch-based promo flux grant operations.
+     * Admin routes — guarded by `ADMIN_EMAILS` allowlist + verified email.
+     * v1 only includes synchronous one-shot promo flux grants.
      */
-    .route('/api/admin/flux-grant-batches', createAdminFluxGrantBatchRoutes(deps.fluxGrantBatchService, deps.env))
+    .route('/api/admin/flux-grants', createAdminFluxGrantsRoutes(deps.adminFluxGrantsService, deps.env))
 
     /**
      * Catch-all 404 in JSON. Replaces hono's default `text/html` "404 Not
@@ -330,13 +328,6 @@ export async function createApp() {
     build: ({ dependsOn }) => createConfigKVService(dependsOn.redis),
   })
 
-  const billingMq = injeca.provide('services:billingMq', {
-    dependsOn: { redis, env: parsedEnv },
-    build: ({ dependsOn }) => createBillingMq(dependsOn.redis, {
-      stream: dependsOn.env.BILLING_EVENTS_STREAM,
-    }),
-  })
-
   const emailService = injeca.provide('services:email', {
     dependsOn: { env: parsedEnv },
     build: ({ dependsOn }) => createEmailService({
@@ -429,13 +420,16 @@ export async function createApp() {
   })
 
   const billingService = injeca.provide('services:billing', {
-    dependsOn: { db, redis, billingMq, configKV, otel },
-    build: ({ dependsOn }) => createBillingService(dependsOn.db, dependsOn.redis, dependsOn.billingMq, dependsOn.configKV, dependsOn.otel?.revenue),
+    dependsOn: { db, redis, configKV, otel },
+    build: ({ dependsOn }) => createBillingService(dependsOn.db, dependsOn.redis, dependsOn.configKV, dependsOn.otel?.revenue),
   })
 
-  const fluxGrantBatchService = injeca.provide('services:adminFluxGrantBatch', {
-    dependsOn: { db },
-    build: ({ dependsOn }) => createFluxGrantBatchService(dependsOn.db),
+  const adminFluxGrantsService = injeca.provide('services:adminFluxGrants', {
+    dependsOn: { db, billingService },
+    build: ({ dependsOn }) => createAdminFluxGrantsService({
+      db: dependsOn.db,
+      billingService: dependsOn.billingService,
+    }),
   })
 
   const ttsMeter = injeca.provide('services:ttsMeter', {
@@ -468,9 +462,8 @@ export async function createApp() {
     requestLogService,
     stripeService,
     billingService,
-    fluxGrantBatchService,
+    adminFluxGrantsService,
     ttsMeter,
-    billingMq,
     configKV,
     redis,
     env: parsedEnv,
@@ -487,9 +480,9 @@ export async function createApp() {
     fluxTransactionService: resolved.fluxTransactionService,
     stripeService: resolved.stripeService,
     billingService: resolved.billingService,
-    fluxGrantBatchService: resolved.fluxGrantBatchService,
+    adminFluxGrantsService: resolved.adminFluxGrantsService,
     ttsMeter: resolved.ttsMeter,
-    billingMq: resolved.billingMq,
+    requestLogService: resolved.requestLogService,
     configKV: resolved.configKV,
     redis: resolved.redis,
     env: resolved.env,