refactor: extract sentiment cog into package with shared _process_finding

Convert cogs/sentiment.py (1050 lines) into cogs/sentiment/ package:
- __init__.py (656 lines): core SentimentCog with new _process_finding()
  that deduplicates the per-user finding loop from _process_buffered and
  _run_mention_scan (~90 lines each → single shared method)
- actions.py: mute_user, warn_user
- topic_drift.py: handle_topic_drift
- channel_redirect.py: handle_channel_redirect, build_channel_context
- coherence.py: handle_coherence_alert
- log_utils.py: log_analysis, log_action, score_color
- state.py: save_user_state, flush_dirty_states

All extracted modules use plain async functions (not methods) receiving
bot/config as parameters. Named log_utils.py to avoid shadowing stdlib
logging. Also update CLAUDE.md with comprehensive project documentation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cogs/sentiment/actions.py

@@ -0,0 +1,123 @@
+import asyncio
+import logging
+from datetime import timedelta
+
+import discord
+
+from cogs.sentiment.log_utils import log_action
+from cogs.sentiment.state import save_user_state
+
+logger = logging.getLogger("bcs.sentiment")
+
+
+async def mute_user(
+    bot, message: discord.Message, score: float,
+    categories: list[str], db_message_id: int | None, dirty_users: set[int],
+):
+    member = message.author
+    if not isinstance(member, discord.Member):
+        return
+
+    if not message.guild.me.guild_permissions.moderate_members:
+        logger.warning("Missing moderate_members permission, cannot mute.")
+        return
+
+    offense_num = bot.drama_tracker.record_offense(member.id)
+    timeout_config = bot.config.get("timeouts", {})
+    escalation = timeout_config.get("escalation_minutes", [5, 15, 30, 60])
+    idx = min(offense_num - 1, len(escalation) - 1)
+    duration_minutes = escalation[idx]
+
+    try:
+        await member.timeout(
+            timedelta(minutes=duration_minutes),
+            reason=f"BCS auto-mute: drama score {score:.2f}",
+        )
+    except discord.Forbidden:
+        logger.warning("Cannot timeout %s — role hierarchy issue.", member)
+        return
+    except discord.HTTPException as e:
+        logger.error("Failed to timeout %s: %s", member, e)
+        return
+
+    messages_config = bot.config.get("messages", {})
+    cat_str = ", ".join(c for c in categories if c != "none") or "general negativity"
+
+    embed = discord.Embed(
+        title=messages_config.get("mute_title", "BREEHAVIOR ALERT"),
+        description=messages_config.get("mute_description", "").format(
+            username=member.display_name,
+            duration=f"{duration_minutes} minutes",
+            score=f"{score:.2f}",
+            categories=cat_str,
+        ),
+        color=discord.Color.red(),
+    )
+    embed.set_footer(
+        text=f"Offense #{offense_num} | Timeout: {duration_minutes}m"
+    )
+
+    await message.channel.send(embed=embed)
+    await log_action(
+        message.guild,
+        f"**MUTE** | {member.mention} | Score: {score:.2f} | "
+        f"Duration: {duration_minutes}m | Offense #{offense_num} | "
+        f"Categories: {cat_str}",
+    )
+
+    logger.info(
+        "Muted %s for %d minutes (offense #%d, score %.2f)",
+        member, duration_minutes, offense_num, score,
+    )
+
+    asyncio.create_task(bot.db.save_action(
+        guild_id=message.guild.id,
+        user_id=member.id,
+        username=member.display_name,
+        action_type="mute",
+        message_id=db_message_id,
+        details=f"duration={duration_minutes}m offense={offense_num} score={score:.2f} categories={cat_str}",
+    ))
+    save_user_state(bot, dirty_users, member.id)
+
+
+async def warn_user(
+    bot, message: discord.Message, score: float,
+    db_message_id: int | None, dirty_users: set[int],
+):
+    timeout_config = bot.config.get("timeouts", {})
+    cooldown = timeout_config.get("warning_cooldown_minutes", 5)
+
+    if not bot.drama_tracker.can_warn(message.author.id, cooldown):
+        return
+
+    bot.drama_tracker.record_warning(message.author.id)
+
+    try:
+        await message.add_reaction("\u26a0\ufe0f")
+    except discord.HTTPException:
+        pass
+
+    messages_config = bot.config.get("messages", {})
+    warning_text = messages_config.get(
+        "warning",
+        "Easy there, {username}. The Breehavior Monitor is watching.",
+    ).format(username=message.author.display_name)
+
+    await message.channel.send(warning_text)
+    await log_action(
+        message.guild,
+        f"**WARNING** | {message.author.mention} | Score: {score:.2f}",
+    )
+
+    logger.info("Warned %s (score %.2f)", message.author, score)
+
+    asyncio.create_task(bot.db.save_action(
+        guild_id=message.guild.id,
+        user_id=message.author.id,
+        username=message.author.display_name,
+        action_type="warning",
+        message_id=db_message_id,
+        details=f"score={score:.2f}",
+    ))
+    save_user_state(bot, dirty_users, message.author.id)