Add replay connector, shared capture scripts, and replay throughput improvements

[jillesvangurp]

Summary

This PR adds the replay connector and shared hub-feed logging tools, and it now also carries the hub-side performance work needed to replay dense traces reliably.

What Changed

• Adds connectors/replay as a diagnostic connector that replays logged location_updates NDJSON back into the hub.
• Supports timestamp correction to replay from "now", acceleration via --acceleration-factor, and synthetic interpolation via --interpolation-rate-hz.
• Adds replay publish batching via --batch-window-ms and --max-batch-size to reduce WebSocket overhead.
• Moves the reusable WebSocket logging and feed-inspection helpers into the shared root scripts/ project and removes connector-local duplicates.
• Updates connector and repository docs to use the shared scripts and describe replay as a diagnostic trace-replay tool.
• Improves hub ingest and fan-out performance with:
  • lazy transforms
  • async native publication and decision-processing stages
  • a future-ready insertion point for filtered track processing before fence/collision evaluation
  • batched WebSocket fan-out
  • drop-on-overload behavior for non-critical queues instead of synchronous backpressure
  • runtime drop counters and larger configurable buffers
  • collision prefiltering against active motions

Why

The repository needed a connector-agnostic way to capture and replay traces for diagnostics and regression testing, and dense replay traces exposed that the hub was doing too much synchronous work on the ingest path.

Replay Verification

Using the same captured OpenSky trace replayed with --interpolation-rate-hz 10.0:

• scheduled emissions: 13,192
• earlier replay branch baseline: 256 observed location items before the perf work
• first async hub pass: 8,639 observed location items
• current branch after batching and fan-out changes: 13,192 observed location items
• fence events matched the live capture at 126

Validation

• uv lock --project connectors/replay
• uv lock --project scripts
• python3 -m py_compile scripts/*.py connectors/replay/*.py
• just bootstrap
• just generate
• just check
• live OpenSky capture and replay validation against the local demo stack