feat(voice): unify Discord voice↔text session (squash of voice/text-unify)

Voice utterances and text messages on the same Discord channel now share
one Claude session, and Echo's voice replies are mirrored back into the
text channel. Replaces the old voice:<id> session-key split.

Changes:
- src/adapters/_text_chunks.py: new leaf module for split_message
  (used by both discord_bot and voice pipeline)
- src/router.py: drop voice: prefix from session_key; add [voice] marker;
  strip leading [speaker:/[voice] tokens from user input (anti-jailbreak);
  remove dead double-clear of voice: key
- src/claude_session.py: include personality/VOICE_MODE.md unconditionally
  (rules become per-turn-aware via [speaker:] prefix instead of session flag)
- src/voice/pipeline.py: VoiceSession splits text_channel_id +
  voice_channel_id; resolve text channel per-send (no stale refs); mirror
  Echo's reply text into the text channel after route_message returns
- src/adapters/discord_voice.py: /voice join passes both channel ids
- src/adapters/discord_bot.py: import split_message from leaf module
- personality/VOICE_MODE.md: rewrite as per-turn dynamic rules;
  add synthesis instructions for text turns after voice turns

Tests:
- tests/test_router.py: 4 new cases (plain channel_id, anti-jailbreak,
  text-adapter regression, no-double-clear)
- tests/test_pipeline_mirror.py: new — Echo reply mirror chunking,
  empty guard, mirror_enabled=False, send-raises resilience
- tests/test_voice_session_channel_ids.py: new — split-attr contract
  + metrics payload schema
- tests/test_voice_session_cleanup.py: update for new kwargs

Plan: /home/moltbot/.claude/plans/vreau-ca-tot-textul-greedy-rivest.md

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

tests/test_pipeline_mirror.py

@@ -0,0 +1,124 @@
+"""Echo-reply text mirror: VoiceSession.on_segment_done forwards Claude's
+reply back into the originating text channel, chunked to Discord's 2000-char
+limit, gated on mirror_enabled, and resilient to send failures.
+
+The pipeline calls router.route_message via the injected
+`router_route_message` seam so tests can drive the reply text without
+monkey-patching modules or invoking the real Claude subprocess.
+"""
+from __future__ import annotations
+
+import asyncio
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from src.voice.pipeline import VoiceSession
+
+
+def _make_text_channel(send_mock: AsyncMock) -> MagicMock:
+    tc = MagicMock(name="text_channel")
+    tc.send = send_mock
+    return tc
+
+
+def _make_session(
+    *,
+    reply_text: str,
+    text_channel,
+    mirror_enabled: bool = True,
+) -> VoiceSession:
+    bot = MagicMock(name="bot")
+    bot.get_channel = MagicMock(return_value=text_channel)
+    bot.get_user = MagicMock(return_value=None)
+    ttsq = MagicMock(name="ttsq")
+    ttsq.push_text = MagicMock()
+    ttsq.clear = MagicMock()
+    route_mock = MagicMock(name="route_message", return_value=(reply_text, False))
+    return VoiceSession(
+        text_channel_id=1001,
+        voice_channel_id=2002,
+        guild_id=42,
+        voice_client=MagicMock(name="voice_client"),
+        bot=bot,
+        ttsq=ttsq,
+        whitelist=set(),
+        record_enabled=False,
+        mirror_enabled=mirror_enabled,
+        transcripts_jsonl_path=None,
+        loop=asyncio.get_event_loop_policy().new_event_loop(),
+        router_route_message=route_mock,
+    )
+
+
+def _reply_chunks(send_mock: AsyncMock) -> list[str]:
+    # Drop the user-mirror call (starts with the 🎤 microphone emoji); the
+    # rest are reply chunks.
+    return [
+        call.args[0]
+        for call in send_mock.call_args_list
+        if not call.args[0].startswith("\U0001f3a4")
+    ]
+
+
+@pytest.mark.asyncio
+async def test_long_reply_splits_into_multiple_chunks():
+    long_reply = "răspuns lung " * 200  # ~2600 chars → ≥2 chunks at 2000-char limit
+    send_mock = AsyncMock(name="text_send")
+    text_channel = _make_text_channel(send_mock)
+    session = _make_session(reply_text=long_reply, text_channel=text_channel)
+
+    await session.on_segment_done(speaker_id=123, text="salut", no_speech_prob=0.1)
+
+    chunks = _reply_chunks(send_mock)
+    assert len(chunks) >= 2
+    assert "".join(chunks).replace("\n", "").strip().startswith("răspuns lung")
+
+
+@pytest.mark.asyncio
+async def test_empty_reply_emits_no_reply_chunks():
+    send_mock = AsyncMock(name="text_send")
+    text_channel = _make_text_channel(send_mock)
+    session = _make_session(reply_text="", text_channel=text_channel)
+
+    await session.on_segment_done(speaker_id=123, text="salut", no_speech_prob=0.1)
+
+    assert _reply_chunks(send_mock) == []
+
+
+@pytest.mark.asyncio
+async def test_whitespace_only_reply_emits_no_reply_chunks():
+    send_mock = AsyncMock(name="text_send")
+    text_channel = _make_text_channel(send_mock)
+    session = _make_session(reply_text="   \n\t  ", text_channel=text_channel)
+
+    await session.on_segment_done(speaker_id=123, text="salut", no_speech_prob=0.1)
+
+    assert _reply_chunks(send_mock) == []
+
+
+@pytest.mark.asyncio
+async def test_mirror_disabled_sends_nothing():
+    send_mock = AsyncMock(name="text_send")
+    text_channel = _make_text_channel(send_mock)
+    session = _make_session(
+        reply_text="orice răspuns", text_channel=text_channel, mirror_enabled=False,
+    )
+
+    await session.on_segment_done(speaker_id=123, text="salut", no_speech_prob=0.1)
+
+    assert send_mock.call_count == 0
+
+
+@pytest.mark.asyncio
+async def test_send_failure_is_swallowed(caplog):
+    send_mock = AsyncMock(name="text_send", side_effect=RuntimeError("discord 500"))
+    text_channel = _make_text_channel(send_mock)
+    session = _make_session(reply_text="răspuns scurt", text_channel=text_channel)
+
+    with caplog.at_level("WARNING"):
+        # Must not raise — both user-mirror and reply-mirror trap exceptions.
+        await session.on_segment_done(speaker_id=123, text="salut", no_speech_prob=0.1)
+
+    # At least one warning was logged for a mirror send failure.
+    assert any("mirror" in rec.message.lower() for rec in caplog.records)