Problem: the single `do_login_and_submit` page action navigated between
pages within one `session.fetch` call, which was fragile and couldn't
leverage `solve_cloudflare` for the Turnstile gate on the submit page.
The submit button click also blocked on navigation completion, causing
timeouts when CF was slow to process.
Solution: split into three separate `session.fetch` calls (homepage
login check, `/enter` login, `/contest/{id}/submit`) with
`solve_cloudflare=True` on login and submit. Use `no_wait_after=True`
on the submit click with a doubled nav timeout. Extract `span.error`
text on submit failure instead of a generic timeout message.
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: Codeforces submit was a stub returning "not yet implemented".
Solution: use StealthySession (same pattern as AtCoder) to handle
Cloudflare Turnstile on the login page, fill credentials, navigate to
the contest submit form, upload source via file input, and cache
cookies at `~/.cache/cp-nvim/codeforces-cookies.json` so repeat
submits skip the login entirely. Uses a single browser page action
that checks for the submit form before navigating, avoiding redundant
page loads and Turnstile challenges.
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.
