## Problem
Two gaps in the plugin: (1) contest pickers have no way to know whether
a contest supports countdown (race), so the UI can't surface that
affordance; (2) `:CP submit` hardcodes a single language ID per platform
with no way to choose C++ standard or override the platform ID.
## Solution
**Race countdown** (`4e709c8`): Add `supports_countdown` boolean to
`ContestListResult` and wire it through CSES/USACO scrapers, cache, race
module, and pickers.
**Language version selection** (`b90ac67`): Add `LANGUAGE_VERSIONS` and
`DEFAULT_VERSIONS` tables in `constants.lua`. Config gains `version` and
`submit_id` fields validated at setup time. `submit.lua` resolves the
effective config to a platform ID (priority: `submit_id` > `version` >
default). Helpdocs add `*cp-submit-language*` section. Tests cover
`LANGUAGE_IDS` completeness.
## Problem
Kattis and USACO had zero offline test coverage — no fixtures, no
conftest
routers, and no entries in the test matrix. The `precision` field and
error
paths were also unverified across all platforms.
## Solution
Add HTML fixtures for both platforms and wire up `httpx.AsyncClient.get`
routers in `conftest.py` following the existing CSES/CodeChef pattern.
Extend the test matrix from 12 to 23 parametrized cases. Add a dedicated
test for the Kattis contest-vs-slug fallback path (verifying
`contest_url`
and `standings_url`), three parametrized metadata error cases, and a
targeted assertion that `extract_precision` returns a non-`None` float
for
problems with floating-point tolerance hints.
Closes#281.
