Problem: each scraper defined its own timeout constants
(`TIMEOUT_S`, `TIMEOUT_SECONDS`) with inconsistent values (15s vs 30s)
and browser timeouts were scattered as magic numbers (60000, 15000,
5000, 500).
Solution: introduce `scrapers/timeouts.py` with named constants for
HTTP requests, browser session/navigation/element/turnstile/settle
timeouts, and submission polling. All six scrapers now import from
the shared module.
Problem: every `:CP submit` on CSES ran the full 5-request login flow
(~1.5 s overhead) even when the token from a previous submit was still
valid.
Solution: persist the API token in credentials via a `credentials`
ndjson event. On subsequent submits, validate the cached token with a
single GET before falling back to the full login.
## Problem
CSES submit was a stub returning "not yet implemented".
## Solution
Authenticate via web login + API token bridge (POST `/login` form, then
POST `/api/login` and confirm the auth page), submit source to
`/api/courses/problemset/submissions` with base64-encoded content, and
poll for verdict. Uses the same username/password credential model as
AtCoder — no browser dependencies needed. Tested end-to-end with a real
CSES account (verdict: `ACCEPTED`).
Also updates `scraper.lua` to pass the full ndjson event object to
`on_status` and handle `credentials` events for future platform use.
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.
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.
