refactor(server): split services into domain/adapter layers, drop dead code

Why
- src/services/ was an unordered mix of single-file services and module
  directories with no shared classification axis, plus several long-dead
  admin batch helpers that survived the move to the simpler synchronous
  admin-flux-grants flow.

What
- services/ now has two top-level layers:
    domain/   — DB state + business rules (billing, characters, chats,
                flux, flux-transaction, llm-router, providers, request-log,
                stripe, user-deletion, admin/{flux-grants,router-config})
    adapters/ — thin wrappers over external SDKs / infra (config-kv, email,
                posthog, tts/)
- admin/* moved under domain/admin/ with consistent plural names
  (flux-grants, router-config).
- tts-adapters/ collapsed to adapters/tts/ (no redundant -adapters suffix
  once nested under adapters/).
- 63 src files + scripts/e2e-llm-router.ts + tests/verifications/_harness.ts
  had relative imports rewritten; git mv preserves blame.
- apps/server/CLAUDE.md and docs/ai-context/*.md updated to match new paths.

Dead code removed
- services/admin-flux-grant-batches/ (service + worker + tests, 1090 LOC) —
  superseded by admin-flux-grants and never wired into app.ts.
- routes/admin/flux-grant-batches/ — same.
- utils/redis-compressed.ts + test — zero production call sites.
- llm-router/index.ts re-exports trimmed from 26 to 6; only symbols with
  external consumers are kept.

Intentionally kept
- schemas/flux-grant-batch.ts and its schemas/index.ts export remain so the
  drizzle-kit generate diff stays empty. Removing them is a separate PR
  that owns the drop-table migration for flux_grant_batch /
  flux_grant_batch_recipient.

Verification
- pnpm -F @proj-airi/server typecheck: passes.
- pnpm exec eslint apps/server: 49 errors, identical to main baseline
  (all are pre-existing node/prefer-global/buffer in envelope-crypto and
  scripts/e2e-llm-router; untouched by this change).
- Vitest passes per-file; the 6 mockDB hook timeouts under full-parallel
  run are the known pushSchema-per-worker infra cost, not a regression.

apps/server/scripts/e2e-llm-router.ts

@@ -21,8 +21,8 @@ import { env, exit } from 'node:process'
 import Redis from 'ioredis'
 
 import { parseEnv } from '../src/libs/env'
-import { createConfigKVService } from '../src/services/config-kv'
-import { createLlmRouterService } from '../src/services/llm-router'
+import { createConfigKVService } from '../src/services/adapters/config-kv'
+import { createLlmRouterService } from '../src/services/domain/llm-router'
 import { createEnvelopeCrypto } from '../src/utils/envelope-crypto'
 
 async function main() {