docs: add AGENTS.md per module and unify ports to 70XX

- Add CLAUDE.md at root and AGENTS.md in apps/api, apps/indexer,
  apps/backoffice, crates/parsers with module-specific guidelines
- Unify all service ports to 70XX (no more internal/external split):
  API 7080, Indexer 7081, Backoffice 7082
- Update docker-compose.yml, Dockerfiles, config.rs defaults,
  .env.example, backoffice routes, bench.sh, smoke.sh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

infra/bench.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-BASE_API="${BASE_API:-http://127.0.0.1:8080}"
+BASE_API="${BASE_API:-http://127.0.0.1:7080}"
 TOKEN="${API_TOKEN:-stripstream-dev-bootstrap-token}"
 
 measure() {