Fetching:
- Add `fetch service`, which runs a worker per enabled source until
SIGINT/SIGTERM (internal/fetcher)
- Add util.Worker: runs a task on an interval with a since-checkpoint
that only advances on success, and a shutdown timeout for in-flight
work; plus AwaitTask/AwaitTaskE for calls that ignore cancellation
- Add fts_mock and sleeper sources
- Sleeper: sleeps periodically to emulate work being done. Can be
instructed to block the shutdown signal or handle it cleanly
Mock FTS server (cmd/mock-fts, internal/mock/findATender):
- Serves GET /api/1.0/ocdsReleasePackages with FTS paging, query
validation, UK local time handling and per-client rate limiting
- Generates fictional releases from an embedded catalog, moving
procedures through planning, tender and award, and keeps them in a
JSON Lines store that survives restarts
- Add logging.AccessLog for combined/common access logs
bwilliams