Arena: normalise-then-match blocklist (leetspeak, stretched spellings, plurals) — a plural slur got past the regex version

ddiff --git a/server/arena/arena-service.js b/server/arena/arena-service.js
iindex 96f0b8ef..6262ba20 100644
---- a/server/arena/arena-service.js
++++ b/server/arena/arena-service.js
@@@ -69,32 +69,33 @@ const HYPE_PATTERNS = ["let's go", 'lets go', 'no way', 'oh my god', 'insane', '
  // the live hot-mic line. Deliberately broad — a false positive costs one quote, a false
  // negative puts a slur on a public page. (Spelling variants: repeated letters, common
  // leetspeak, and word-boundary aware so "hell" does not catch "shell".)
--const BANNED_PATTERNS = [
--    /n+[i1!]+g+(?:a+|e+r+|u+h+|r+)s?\b/i,
--    /\bf+[a@]+g+(?:o+t+|s|z)?\b/i,
--    /\br+[e3]+t+[a@]+r+d+(?:ed|s)?\b/i,
--    /\bt+r+[a@]+n+n+(?:y|ie|ies)\b/i,
--    /\bk+[i1]+k+e+s?\b/i,
--    /\bs+p+[i1]+c+k?s?\b/i,
--    /\bc+h+[i1]+n+k+s?\b/i,
--    /\bg+[o0]+[o0]+k+s?\b/i,
--    /\bw+e+t+b+a+c+k+s?\b/i,
--    /\bd+[y1]+k+e+s?\b/i,
--    /\bc+u+n+t+s?\b/i,
--    /\bw+h+[o0]+r+e+s?\b/i,
--    /\bs+l+u+t+s?\b/i,
--    /\bp+u+s+s+(?:y|ies)\b/i,
--    /\b(?:d+[i1]+c+k|c+[o0]+c+k)s?\b/i,
--    /\br+a+p+(?:e|ed|ing|ist)\b/i,
--    /\bk+y+s+\b/i,
--    /\bkill\s+(?:yourself|urself|himself|herself|themselves)\b/i,
--    /\b(?:hitler|nazi|nazis)\b/i,
--    /\bmolest/i,
--    /\bpedo/i,
++// Stems are matched on a NORMALISED copy of the text: lower-cased, leetspeak folded
++// (1→i 3→e 4→a 0→o @→a $→s !→i), runs of 3+ identical letters collapsed to 2, and
++// punctuation stripped — so "f4gg0tz", "niggaaa", "r3tards" all reduce to the stems
++// below. Each stem may carry a plural/verb suffix.
++const BANNED_STEMS = [
++    'nigga', 'nigger', 'niggu', 'fag', 'faggot', 'fagot', 'retard', 'tranny', 'trannie', 'kike', 'spic', 'spick', 'chink', 'gook',
++    'wetback', 'dyke', 'cunt', 'whore', 'slut', 'pussy', 'pussies', 'dick', 'cock', 'rape', 'rapist', 'kys', 'hitler', 'nazi',
++    'molest', 'molester', 'pedo', 'pedophile', 'paedo', 'coon', 'raghead', 'towelhead', 'beaner',
  ];
++const SUFFIX = '(?:s|es|z|ed|ing|er|ers)?';
++const BANNED_STEM_RE = new RegExp(`\\b(?:${BANNED_STEMS.join('|')})${SUFFIX}\\b`, 'i');
++// Fully collapsed variants ("niggaaaa" → "niga", "faggot" → "fagot") catch stretched spellings.
++const collapseRepeats = (t) => t.replace(/([a-z])\1+/g, '$1');
++const BANNED_STEM_COLLAPSED_RE = new RegExp(`\\b(?:${[...new Set(BANNED_STEMS.map(collapseRepeats))].join('|')})${SUFFIX}\\b`, 'i');
++const BANNED_PHRASES = [/\bkill\s+(?:your|ur|him|her|them)\s*sel(?:f|ves)\b/i, /\bgo\s+die\b/i];
++
++function normalizeForFilter(text) {
++    return String(text || '')
++        .toLowerCase()
++        .replace(/[1!]/g, 'i').replace(/3/g, 'e').replace(/[4@]/g, 'a').replace(/0/g, 'o').replace(/\$/g, 's')
++        .replace(/[^a-z\s]/g, ' ');
++}
  function isBannedText(text) {
--    const t = String(text || '');
--    return BANNED_PATTERNS.some(re => re.test(t));
++    const raw = String(text || '');
++    if (BANNED_PHRASES.some(re => re.test(raw))) return true;
++    const norm = normalizeForFilter(raw);
++    return BANNED_STEM_RE.test(norm) || BANNED_STEM_COLLAPSED_RE.test(collapseRepeats(norm));
  }
  
  // ── Tables ───────────────────────────────────────────────────
ddiff --git a/test/arena.test.js b/test/arena.test.js
iindex 78a98e36..932d173e 100644
---- a/test/arena.test.js
++++ b/test/arena.test.js
@@@ -91,7 +91,7 @@ db.addTimelineEvents([
      { stream_id: s1, user_id: u1, vod_id: 901, kind: 'speech', start_sec: 5100, end_sec: 5110, text: 'No way, chat, that guy is such a retard!', label: null, confidence: 0.9 },
      { stream_id: s1, user_id: u1, vod_id: 901, kind: 'speech', start_sec: 5200, end_sec: 5210, text: 'Holy, that was insane, kill yourself if you disagree!', label: null, confidence: 0.9 },
  ]);
--for (const bad of ["what up my n1ggas", "stop being a faggot", "he's a retard", "kys", "kill yourself", "such a whore", "pussy move"]) assert.ok(arena._isBannedText(bad), `banned: ${bad}`);
++for (const bad of ["what up my n1ggas", "stop being a faggot", "keep it real on those faggots", "niggers", "r3tards everywhere", "he's a retard", "kys", "kill yourself", "such a whore", "pussy move", "f4gg0tz", "niggaaaa"]) assert.ok(arena._isBannedText(bad), `banned: ${bad}`);
  for (const ok of ["the shell script is hell to debug", "we dug a dyke in the sand? no — a dike, the engineering kind"]) { /* documented: broad filter may catch "dyke" — acceptable */ }
  assert.ok(!arena._isBannedText("the shell script is hell to debug and I hate it"), 'ordinary sentences pass');
  const cands = arena._quoteCandidates(u1);