Implement GuardDen Discord moderation bot

Features:
- Core moderation: warn, kick, ban, timeout, strike system
- Automod: banned words filter, scam detection, anti-spam, link filtering
- AI moderation: Claude/OpenAI integration, NSFW detection, phishing analysis
- Verification system: button, captcha, math, emoji challenges
- Rate limiting system with configurable scopes
- Event logging: joins, leaves, message edits/deletes, voice activity
- Per-guild configuration with caching
- Docker deployment support

Bug fixes applied:
- Fixed await on session.delete() in guild_config.py
- Fixed memory leak in AI moderation message tracking (use deque)
- Added error handling to bot shutdown
- Added error handling to timeout command
- Removed unused Literal import
- Added prefix validation
- Added image analysis limit (3 per message)
- Fixed test mock for SQLAlchemy model

src/guardden/models/guild.py

@@ -0,0 +1,117 @@
+"""Guild-related database models."""
+
+from datetime import datetime
+from typing import TYPE_CHECKING
+
+from sqlalchemy import Boolean, ForeignKey, Integer, String, Text
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from guardden.models.base import Base, SnowflakeID, TimestampMixin
+
+if TYPE_CHECKING:
+    from guardden.models.moderation import ModerationLog, Strike
+
+
+class Guild(Base, TimestampMixin):
+    """Represents a Discord guild (server) configuration."""
+
+    __tablename__ = "guilds"
+
+    id: Mapped[int] = mapped_column(SnowflakeID, primary_key=True)
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    owner_id: Mapped[int] = mapped_column(SnowflakeID, nullable=False)
+    premium: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+
+    # Relationships
+    settings: Mapped["GuildSettings"] = relationship(
+        back_populates="guild", uselist=False, cascade="all, delete-orphan"
+    )
+    banned_words: Mapped[list["BannedWord"]] = relationship(
+        back_populates="guild", cascade="all, delete-orphan"
+    )
+    moderation_logs: Mapped[list["ModerationLog"]] = relationship(
+        back_populates="guild", cascade="all, delete-orphan"
+    )
+    strikes: Mapped[list["Strike"]] = relationship(
+        back_populates="guild", cascade="all, delete-orphan"
+    )
+
+
+class GuildSettings(Base, TimestampMixin):
+    """Per-guild bot settings and configuration."""
+
+    __tablename__ = "guild_settings"
+
+    guild_id: Mapped[int] = mapped_column(
+        SnowflakeID, ForeignKey("guilds.id", ondelete="CASCADE"), primary_key=True
+    )
+
+    # General settings
+    prefix: Mapped[str] = mapped_column(String(10), default="!", nullable=False)
+    locale: Mapped[str] = mapped_column(String(10), default="en", nullable=False)
+
+    # Channel configuration (stored as snowflake IDs)
+    log_channel_id: Mapped[int | None] = mapped_column(SnowflakeID, nullable=True)
+    mod_log_channel_id: Mapped[int | None] = mapped_column(SnowflakeID, nullable=True)
+    welcome_channel_id: Mapped[int | None] = mapped_column(SnowflakeID, nullable=True)
+
+    # Role configuration
+    mute_role_id: Mapped[int | None] = mapped_column(SnowflakeID, nullable=True)
+    verified_role_id: Mapped[int | None] = mapped_column(SnowflakeID, nullable=True)
+    mod_role_ids: Mapped[dict] = mapped_column(JSONB, default=list, nullable=False)
+
+    # Moderation settings
+    automod_enabled: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    anti_spam_enabled: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    link_filter_enabled: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+
+    # Strike thresholds (actions at each threshold)
+    strike_actions: Mapped[dict] = mapped_column(
+        JSONB,
+        default=lambda: {
+            "1": {"action": "warn"},
+            "3": {"action": "timeout", "duration": 3600},
+            "5": {"action": "kick"},
+            "7": {"action": "ban"},
+        },
+        nullable=False,
+    )
+
+    # AI moderation settings
+    ai_moderation_enabled: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    ai_sensitivity: Mapped[int] = mapped_column(Integer, default=50, nullable=False)  # 0-100 scale
+    nsfw_detection_enabled: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+
+    # Verification settings
+    verification_enabled: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    verification_type: Mapped[str] = mapped_column(
+        String(20), default="button", nullable=False
+    )  # button, captcha, questions
+
+    # Relationship
+    guild: Mapped["Guild"] = relationship(back_populates="settings")
+
+
+class BannedWord(Base, TimestampMixin):
+    """Banned words/phrases for a guild with regex support."""
+
+    __tablename__ = "banned_words"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    guild_id: Mapped[int] = mapped_column(
+        SnowflakeID, ForeignKey("guilds.id", ondelete="CASCADE"), nullable=False
+    )
+
+    pattern: Mapped[str] = mapped_column(Text, nullable=False)
+    is_regex: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    action: Mapped[str] = mapped_column(
+        String(20), default="delete", nullable=False
+    )  # delete, warn, strike
+    reason: Mapped[str | None] = mapped_column(Text, nullable=True)
+
+    # Who added this and when
+    added_by: Mapped[int] = mapped_column(SnowflakeID, nullable=False)
+
+    # Relationship
+    guild: Mapped["Guild"] = relationship(back_populates="banned_words")