fix(voice): stop backtick TTS crash and actually count error turns

Claude replies with markdown/backticks by default; MeloTTS's Korean text
normaliser has no entry for '`' and dies with KeyError: '`', so any reply
mentioning a command/code block crashed the whole voice turn (500 on
/api/voice-turn). Fix at the shared synth() choke point with
normalize_for_speech(), which flattens code fences/inline code/links/markdown
and guarantees no backtick reaches the worker — covering both the dashboard
voice turn and the Discord speak() bridge. Also add a PERSONA line asking the
model to avoid markdown (belt-and-suspenders; the code strip is the real fix).

errors_total never moved for turn-level failures: it was only bumped by
log("error") events, and the dashboard voice path calls turn.finish(error=...)
without logging. Emit one error-level log event from Turn.finish() when a turn
ends in error, so both the server counter and the browser SSE mirror stay
consistent, guarded to count at most once. Drop the now-redundant pipeline
log("error") to avoid double counting and remove the dead _publish stub.

Verified: raw backtick -> worker KeyError '`' reproduced; after fix real
MeloTTS synth of a backtick+fenced reply succeeds; /api/voice-turn returns 200
with a wav body on a backtick reply and errors_total stays 0, and an induced
synth failure returns 500 with errors_total incrementing to exactly 1. Full
suite 18 passed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

wsai/backends/claude.py

@@ -125,7 +125,8 @@ class ClaudeBrain:
     PERSONA = (
         "너는 사용자의 디스코드 화면공유를 실시간으로 함께 보는 AI 파트너야. "
         "화면 설명을 참고해 자연스러운 반말/존댓말은 사용자에 맞추고, 짧고 대화하듯 답해. "
-        "화면을 못 봤으면 솔직히 말해."
+        "화면을 못 봤으면 솔직히 말해. "
+        "네 답변은 음성으로 읽히니 마크다운·코드블록·백틱 같은 서식 없이 평범한 말로만 답해."
     )
 
     def __init__(self, *, model: str = "claude-sonnet-4-5", api_key: str | None = None) -> None:

wsai/backends/melo.py

@@ -22,6 +22,7 @@ import collections
 import json
 import logging
 import os
+import re
 import time
 from pathlib import Path
 from typing import Awaitable, Callable
@@ -32,6 +33,42 @@ log = logging.getLogger("wsai.tts.melo")
 
 _DEFAULT_PYTHON = "/home/claude/jarvis-tts/melo311/bin/python"
 
+_FENCE_RE = re.compile(r"```[^\n`]*\n?(.*?)```", re.DOTALL)
+_LINK_RE = re.compile(r"\[([^\]]+)\]\([^)]*\)")
+_INLINE_CODE_RE = re.compile(r"`+([^`]*)`+")
+
+
+def normalize_for_speech(text: str) -> str:
+    """Flatten Claude's markdown/code formatting into plain prose before TTS.
+
+    MeloTTS's Korean text normaliser has no dictionary entry for characters
+    like the backtick and dies with ``KeyError: '`'`` — which crashes the whole
+    voice turn the moment the model mentions a command or shows a code block.
+    Code/markdown also reads terribly aloud. So strip the formatting and keep
+    the words. Every spoken path (dashboard voice turn and the Discord speak()
+    bridge) funnels through ``synth()``, so normalising there covers them both.
+    """
+    if not text:
+        return text
+    # Fenced code block -> keep its inner text as spoken words, drop the fences.
+    text = _FENCE_RE.sub(lambda m: " " + m.group(1) + " ", text)
+    # [label](url) -> label
+    text = _LINK_RE.sub(r"\1", text)
+    # `code` -> code
+    text = _INLINE_CODE_RE.sub(r"\1", text)
+    # Any stray/unbalanced backtick that survived -> gone. This is the exact
+    # character that crashes MeloTTS, so guarantee none remain.
+    text = text.replace("`", "")
+    # Markdown structure markers -> plain text.
+    text = re.sub(r"(?m)^\s{0,3}#{1,6}\s*", "", text)   # ATX headings
+    text = re.sub(r"(?m)^\s{0,3}>\s?", "", text)         # blockquotes
+    text = re.sub(r"(?m)^\s{0,3}[-*+]\s+", "", text)     # bullet list markers
+    text = re.sub(r"[*_]{1,3}", "", text)                # bold/italic emphasis
+    # Collapse the whitespace the stripping leaves behind.
+    text = re.sub(r"[ \t]+", " ", text)
+    text = re.sub(r"\n{2,}", "\n", text)
+    return text.strip()
+
 # A sink receives the finished wav path plus the reply it voices.
 Sink = Callable[[str, Reply], Awaitable[None]]
 
@@ -135,6 +172,7 @@ class MeloTTS:
         """Synthesize `text` to a wav and return its path (no sink). Reusable by
         callers that want the wav directly (e.g. the Discord voice bridge)."""
         await self._ensure()
+        text = normalize_for_speech(text)
         self._n += 1
         out = str(self.out_dir / f"tts-{self._n:06d}.wav")
         req = json.dumps({"text": text, "out": out, "speed": self.speed})