## Problem
`_submit_sync` was a 170-line nested closure with `_solve_turnstile` and
the browser-install block further nested inside it. Status events went
to
stderr, which `run_scraper()` silently discards, leaving the user with a
10–30s silent hang after credential entry. The NDJSON spawn path also
lacked stdin support, so submit had no streaming path at all.
## Solution
Extract `_TURNSTILE_JS`, `_solve_turnstile`, `_ensure_browser`, and
`_submit_headless` to module level in `atcoder.py`; status events
(`installing_browser`, `checking_login`, `logging_in`, `submitting`) now
print to stdout as NDJSON. Add stdin pipe support to the NDJSON spawn
path in `scraper.lua` and switch `M.submit` to streaming with an
`on_status` callback. Wire `on_status` in `submit.lua` to fire
`vim.notify` for each phase transition.
Problem: scrape_contest_list paginated the entire Kattis problem database
(3000+ problems) treating each as a "contest". scrape_contest_metadata
only handled single-problem access. stream_tests_for_category_async could
not fetch tests for multiple problems in a real contest.
Solution: replace the paginated problem loop with a single GET to
/contests that returns ~150 real timed contests. Add contest-aware path
to scrape_contest_metadata that fetches /contests/{id}/problems and
returns all problem slugs; fall back to single-problem path when the ID
is not a contest. Add _stream_single_problem helper and update
stream_tests_for_category_async to fan out concurrently over all contest
problem slugs before falling back to the single-problem path.
Problem: lua typecheck flagged missing start_time field on ContestSummary;
ty flagged BeautifulSoup Tag/NavigableString union on csrf_input.get(),
a 3-tuple unpack where _extract_problem_info now returns 4 values in
cses.py, and an untyped list assignment in usaco.py.
Solution: add start_time? to ContestSummary LuaDoc, guard csrf_input
with hasattr check and type: ignore, unpack precision from
_extract_problem_info in cses.py callers, and use cast() in usaco.py.
Add submit.lua that reads credentials from a local JSON store (prompting
via vim.ui.input/inputsecret on first use), reads the source file, and
delegates to scraper.submit(). Add language_ids.py with platform-to-
language-ID mappings for atcoder, codeforces, and cses.
Add KattisScraper and USACOScraper with contest list, metadata, and
test case fetching. Register kattis and usaco in PLATFORMS,
PLATFORM_DISPLAY_NAMES, and default platform configs.
Problem: problem pages contain floating-point precision requirements and
contest start timestamps that were not being extracted or stored. The
submit workflow also needed a foundation in the scraper layer.
Solution: add extract_precision() to base.py and propagate through all
scrapers into cache. Add start_time to ContestSummary and extract it
from AtCoder and Codeforces. Add SubmitResult model, abstract submit()
method, submit CLI case with get_language_id() resolution, stdin/env_extra
support in run_scraper, and a full AtCoder submit implementation; stub
the remaining platforms.
