## Problem
There was no way to open a problem, contest, or standings page in the
browser from within the plugin.
## Solution
Add `contest_url` and `standings_url` to `MetadataResult` and persist
them in the cache. Add `cache.get_open_urls` to resolve all three URLs.
Wire up `:CP open [problem|contest|standings]` in `commands/init.lua`
to call `vim.ui.open`, warning when a URL is unavailable (e.g. CSES
has no standings). Closes#315.
## Problem
Credentials lived in a top-level `_credentials` namespace, requiring
special
preservation logic in `clear_all()` and a separate key hierarchy from
the
platform data they belong to.
## Solution
Move credentials from `_credentials.<platform>` to
`<platform>._credentials`.
Migrate v1 caches on load, skip underscore-prefixed keys when
enumerating
contest IDs and summaries, and simplify `clear_all()` now that no
special
preservation is needed.
Stacked on #292.
Problem: :CP login was a poor API — no way to clear credentials without
raw Lua, and the single command didn't scale to multiple operations.
Solution: replace login with a :CP credentials subcommand following the
same pattern as :CP cache. :CP credentials set [platform] prompts and
saves; :CP credentials clear [platform] removes one or all platforms.
Add cache.clear_credentials(), rename login.lua to credentials.lua,
update parse/dispatch/tab-complete, and rewrite vimdoc accordingly.
Problem: credentials were stored in a separate file,
cp-nvim-credentials.json, alongside the main cp-nvim.json cache.
Two files for one plugin's persistent state was unnecessary.
Solution: add get_credentials/set_credentials to cache.lua, storing
credentials under _credentials[platform] in the shared cache. Update
clear_all() to preserve _credentials across cache wipes. Remove the
separate file, load_credentials, and save_credentials from submit.lua.
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.
Problem: output comparison used exact string equality after whitespace
normalisation, causing correct solutions to fail on problems where
floating-point answers are accepted within a tolerance (e.g. 1e-6).
Solution: add an optional ui.panel.epsilon config value. When set,
actual and expected output are compared token-by-token: numeric tokens
are compared with math.abs(a - b) <= epsilon, non-numeric tokens fall
back to exact string equality. Per-problem epsilon can also be stored
in the cache and takes precedence over the global default.
Problem: M._cache = cache_data captured the initial empty table reference
at module load time. After M.load() reassigns cache_data to the decoded
JSON, M._cache is permanently stale and returns the wrong table.
Solution: remove the field assignment and expose get_raw_cache() which
closes over cache_data and always returns the current table.
Problem: after an install or update, the on-disk cache may contain data
written by an older version of the plugin whose format no longer matches
what the current code expects.
Solution: embed a CACHE_VERSION in every saved cache file. On load, if
the stored version is missing or differs from the current one, wipe the
cache and rewrite it. Corrupt (non-decodable) cache files are handled
the same way instead of only logging an error.
