fix: expand language IDs, fix AtCoder submit, normalize logging (#353)

## Problem

Language version coverage was incomplete across all platforms, AtCoder
submit used a stale cookie fast-path that caused silent failures, and
raw
`vim.notify` calls throughout the codebase produced inconsistent or
missing `[cp.nvim]:` prefixes.

## Solution

Remove cookie persistence from AtCoder login/submit (always fresh
login),
increase the submit nav timeout to 40s, and switch to in-memory buffer
upload with the correct per-language extension from a full
`_LANGUAGE_ID_EXTENSION`
map covering all 116 AtCoder languages. Expand `LANGUAGE_VERSIONS` in
`constants.lua` with all AtCoder languages, 15 new CF languages with
full
version variants, and 50+ Kattis languages. Fix AtCoder `prolog` ID
(`6079`→`6081`, was Pony) and remove the non-existent `racket` entry.
Replace all raw `vim.notify` calls with `logger.log`. Simplify the
submit
language doc to point at `constants.lua` rather than maintaining a
static table.

lua/cp/race.lua

@@ -239,13 +239,13 @@ function M.start(platform, contest_id, language)
         logger.log('Contest started!', { level = vim.log.levels.INFO, override = true })
         race_try_setup(p, c, l, 1, token)
       elseif should_notify(r) then
-        vim.notify(
-          ('[cp.nvim]: %s race "%s" starts in %s'):format(
+        logger.log(
+          ('%s race "%s" starts in %s'):format(
             constants.PLATFORM_DISPLAY_NAMES[race_state.platform] or race_state.platform,
             race_state.contest_name,
             format_countdown(r)
           ),
-          vim.log.levels.INFO
+          { level = vim.log.levels.INFO, override = true }
         )
       end
     end)