Feat/gtp 5.3 codex rate limit violations batching

[kudroma404]

Summary

This PR adds batched tracking for rate-limit violations so we can observe abuse patterns without writing one DB row per 429.

What changed

• Added a dedicated rate-limit violation tracking pipeline:
  • RateLimitViolationTracker + sink abstraction
  • in-memory aggregation by flush window
  • periodic flush to PostgreSQL
• Added DB persistence support for aggregated violation records.
• Wired tracking into HTTP rate-limit paths so limiter denials contribute to aggregates.
• Threaded tracker through server/state startup so it is available in request handling.
• Added integration test coverage for rate-limit violation tracking behavior.

Schema and config updates

• Added new table: rate_limit_violations in dev-env/init-scripts/init-schema.sql.
• Enabled required JSON handling for Postgres dependency in Cargo.toml / Cargo.lock.
• Added new DB flush config:
  • db.violation_flush_interval_sec
• Updated dev configs:
  • dev-env/config/config-single.toml
  • dev-env/config/config1.toml
  • dev-env/config/config2.toml
  • dev-env/config/config3.toml

Files of interest

• Tracker + DB:
  • src/db/violation_tracker.rs
  • src/db/mod.rs
  • src/db/repository.rs
• HTTP wiring:
  • src/http3/rate_limits.rs
  • src/http3/server.rs
  • src/http3/state.rs
• Bootstrap/state wiring:
  • src/raft/mod.rs
  • src/test_support.rs
• Tests:
  • tests/client_http_api/rate_limit_violations.rs
  • tests/client_http_api/support.rs
  • tests/event_tracker/support.rs

Test plan

• cargo fmt
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-targets --all-features
• cargo test --tests --features test-support
• Trigger repeated requests against a rate-limited endpoint and confirm rows are written to rate_limit_violations with aggregated details.

Notes

• This design intentionally batches and aggregates violations to reduce write amplification.
• Existing rate limiting behavior remains unchanged; this PR adds observability for denial events.