fix: expand language IDs, fix AtCoder submit, normalize logging

Problem: AtCoder submit used a cookie fast-path that silently failed on
stale sessions; `_LANGUAGE_ID_EXTENSION` only covered 2 of 116 languages;
`LANGUAGE_VERSIONS` was incomplete for AtCoder, CF, and Kattis; AtCoder
`prolog` and `racket` entries had wrong IDs. Raw `vim.notify` calls
throughout bypassed `logger.log`, producing inconsistent or missing
`[cp.nvim]:` prefixes.

Solution: Remove cookie persistence from AtCoder login/submit — always
use a fresh login within a single session. Increase
`BROWSER_SUBMIT_NAV_TIMEOUT["atcoder"]` to 40s and switch to in-memory
buffer upload with the correct per-language extension. Expand
`LANGUAGE_VERSIONS` with all 116 AtCoder languages, 15 new CF languages
with full version variants (java8/21, kotlin 1.7/1.9/2.2, rust 2021/2024,
etc.), and 50+ Kattis languages. Fix AtCoder `prolog` ID (`6079`→`6081`,
was Pony) and remove non-existent `racket` entry. Replace all raw
`vim.notify` calls with `logger.log`.

scrapers/kattis.py

@@ -338,13 +338,14 @@ class KattisScraper(BaseScraper):
                 await _save_kattis_cookies(client)
 
             print(json.dumps({"status": "submitting"}), flush=True)
-            ext = "py" if "python" in language_id.lower() else "cpp"
+            lang_lower = language_id.lower()
+            mainclass = Path(file_path).stem if "java" in lang_lower else ""
             data: dict[str, str] = {
                 "submit": "true",
                 "script": "true",
                 "language": language_id,
                 "problem": problem_id,
-                "mainclass": "",
+                "mainclass": mainclass,
                 "submit_ctr": "2",
             }
             if contest_id != problem_id:
@@ -354,7 +355,7 @@ class KattisScraper(BaseScraper):
                 return await client.post(
                     f"{BASE_URL}/submit",
                     data=data,
-                    files={"sub_file[]": (f"solution.{ext}", source, "text/plain")},
+                    files={"sub_file[]": (Path(file_path).name, source, "text/plain")},
                     headers=HEADERS,
                     timeout=HTTP_TIMEOUT,
                 )