chore: remove publisher/scheduler services, prune scripts/

[dotjae]

Summary

• Deletes the standalone publisher/ and scheduler/ directories. Their GTFS-RT builder logic now lives in backend/schedule_engine/tasks.py (build_vehicle_positions, build_trip_updates), and the 15-second beat schedule lives in backend/databus/celery.py app.conf.beat_schedule — explicit in code rather than DB-backed.
• Prunes scripts/ to the survivors: dev.sh, prod.sh, inspect_redis.py, cleanup_redis.py. Removes continuous_simulator.py and redis_seed_data.py (superseded by the external simulator/ repo, which publishes MQTT telemetry to the telemetry-broker), the one-off rename_operation_to_operations.sql, and the per-dir pyproject.toml/uv.lock.
• Output path for generated feeds aligned to backend/feed/files/ per build-gtfs-realtime spec.
• Dev infra: sets PYTHONPYCACHEPREFIX=/tmp/pycache on the four backend services so each container writes bytecode to its own ephemeral path. Without this, the four containers race to rewrite .pyc files in the bind-mounted source tree whenever a heavily-imported file changes, surfacing as OSError: [Errno 35] Resource deadlock avoided on startup. .gitignore updated to drop the obsolete publisher/feed/files/ entries and ignore the new backend/feed/files/*.pb/.json outputs.

Test plan

• docker compose -f compose.dev.yml config parses without publisher or scheduler service entries.
• bash scripts/dev.sh starts cleanly; no crash-loops, no EDEADLK during Django startup.
• From the orchestrator container: from schedule_engine.tasks import build_vehicle_positions, build_trip_updates imports without error and build_vehicle_positions.delay() enqueues against schedule_engine queue.
• After ~15 s of uptime, backend/feed/files/ contains vehicle_positions.{json,pb} and trip_updates.{json,pb}.
• git grep -nE 'publisher/|scheduler/' returns nothing meaningful.