feat(messages): add unified conversation models and migration SQL

Add 5 new SQLAlchemy models (Conversation, ConversationMember, ConvMessage,
MessageReaction, MessagePin) and extend MessageAttachment with conv_message_id FK.
Migration 091 creates all tables with indexes, FKs, and grants.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

database.py

@@ -2344,7 +2344,10 @@ class MessageAttachment(Base):
     mime_type = Column(String(100), nullable=False)
     created_at = Column(DateTime, default=datetime.now)
 
+    conv_message_id = Column(Integer, ForeignKey('conv_messages.id', ondelete='CASCADE'), nullable=True)
+
     message = relationship('PrivateMessage', backref=backref('attachments', cascade='all, delete-orphan'))
+    conv_message = relationship('ConvMessage', back_populates='attachments', foreign_keys=[conv_message_id])
 
 
 # ============================================================
@@ -5820,6 +5823,134 @@ class InternalHealthLog(Base):
         return f'<InternalHealthLog {self.checked_at} app={self.app_ok} db={self.db_ok}>'
 
 
+# ============================================================
+# UNIFIED CONVERSATIONS (messaging redesign)
+# ============================================================
+
+class Conversation(Base):
+    """Zunifikowana konwersacja — 1:1 lub grupowa"""
+    __tablename__ = 'conversations'
+
+    id = Column(Integer, primary_key=True)
+    name = Column(String(255), nullable=True)
+    is_group = Column(Boolean, nullable=False, default=False)
+    owner_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)
+    created_at = Column(DateTime, default=datetime.now)
+    updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)
+    last_message_id = Column(Integer, ForeignKey('conv_messages.id', name='fk_conversations_last_message', use_alter=True, ondelete='SET NULL'), nullable=True)
+
+    owner = relationship('User', foreign_keys=[owner_id])
+    members = relationship('ConversationMember', backref='conversation', cascade='all, delete-orphan')
+    messages = relationship('ConvMessage', backref='conversation',
+                            foreign_keys='ConvMessage.conversation_id',
+                            cascade='all, delete-orphan',
+                            order_by='ConvMessage.created_at')
+    last_message = relationship('ConvMessage', foreign_keys=[last_message_id],
+                                post_update=True)
+    pins = relationship('MessagePin', backref='conversation', cascade='all, delete-orphan')
+
+    @property
+    def display_name(self):
+        """Nazwa wyświetlana — nazwa grupy lub lista imion uczestników"""
+        if self.name:
+            return self.name
+        names = [m.user.name or m.user.email.split('@')[0] for m in self.members if m.user]
+        return ', '.join(sorted(names)[:4]) + (f' +{len(names)-4}' if len(names) > 4 else '')
+
+    @property
+    def member_count(self):
+        return len(self.members)
+
+    def __repr__(self):
+        return f'<Conversation {self.id} group={self.is_group} members={self.member_count}>'
+
+
+class ConversationMember(Base):
+    """Członkostwo w konwersacji"""
+    __tablename__ = 'conversation_members'
+
+    conversation_id = Column(Integer, ForeignKey('conversations.id', ondelete='CASCADE'), primary_key=True)
+    user_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), primary_key=True)
+    role = Column(String(20), nullable=False, default='member')
+    last_read_at = Column(DateTime, nullable=True)
+    is_muted = Column(Boolean, nullable=False, default=False)
+    is_archived = Column(Boolean, nullable=False, default=False)
+    joined_at = Column(DateTime, default=datetime.now)
+    added_by_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)
+
+    user = relationship('User', foreign_keys=[user_id])
+    added_by = relationship('User', foreign_keys=[added_by_id])
+
+    @property
+    def is_owner(self):
+        return self.role == 'owner'
+
+    def __repr__(self):
+        return f'<ConversationMember conv={self.conversation_id} user={self.user_id} role={self.role}>'
+
+
+class ConvMessage(Base):
+    """Wiadomość w konwersacji"""
+    __tablename__ = 'conv_messages'
+
+    id = Column(Integer, primary_key=True)
+    conversation_id = Column(Integer, ForeignKey('conversations.id', ondelete='CASCADE'), nullable=False, index=True)
+    sender_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)
+    content = Column(Text, nullable=False)
+    reply_to_id = Column(Integer, ForeignKey('conv_messages.id', ondelete='SET NULL'), nullable=True)
+    edited_at = Column(DateTime, nullable=True)
+    is_deleted = Column(Boolean, nullable=False, default=False)
+    link_preview = Column(PG_JSONB, nullable=True)
+    created_at = Column(DateTime, default=datetime.now, index=True)
+
+    sender = relationship('User', foreign_keys=[sender_id])
+    reply_to = relationship('ConvMessage', remote_side=[id], foreign_keys=[reply_to_id])
+    reactions = relationship('MessageReaction', backref='message', cascade='all, delete-orphan')
+    attachments = relationship('MessageAttachment',
+                               foreign_keys='MessageAttachment.conv_message_id',
+                               back_populates='conv_message',
+                               cascade='all, delete-orphan')
+
+    def __repr__(self):
+        return f'<ConvMessage {self.id} conv={self.conversation_id} sender={self.sender_id}>'
+
+
+class MessageReaction(Base):
+    """Reakcja emoji na wiadomość"""
+    __tablename__ = 'message_reactions'
+    __table_args__ = (
+        UniqueConstraint('message_id', 'user_id', 'emoji', name='uq_message_reaction'),
+    )
+
+    id = Column(Integer, primary_key=True)
+    message_id = Column(Integer, ForeignKey('conv_messages.id', ondelete='CASCADE'), nullable=False, index=True)
+    user_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
+    emoji = Column(String(10), nullable=False)
+    created_at = Column(DateTime, default=datetime.now)
+
+    user = relationship('User', foreign_keys=[user_id])
+
+    def __repr__(self):
+        return f'<MessageReaction {self.emoji} msg={self.message_id} user={self.user_id}>'
+
+
+class MessagePin(Base):
+    """Przypięta wiadomość w konwersacji"""
+    __tablename__ = 'message_pins'
+
+    id = Column(Integer, primary_key=True)
+    conversation_id = Column(Integer, ForeignKey('conversations.id', ondelete='CASCADE'), nullable=False, index=True)
+    message_id = Column(Integer, ForeignKey('conv_messages.id', ondelete='CASCADE'), nullable=False)
+    pinned_by_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)
+    created_at = Column(DateTime, default=datetime.now)
+
+    message = relationship('ConvMessage', foreign_keys=[message_id])
+    pinned_by = relationship('User', foreign_keys=[pinned_by_id])
+
+    def __repr__(self):
+        return f'<MessagePin msg={self.message_id} conv={self.conversation_id}>'
+
+
 # ============================================================
 # DATABASE INITIALIZATION
 # ============================================================

database/migrations/091_messaging_redesign.sql

@@ -0,0 +1,96 @@
+-- 091_messaging_redesign.sql
+-- Unified conversation model: replaces separate private_messages + message_group
+-- Conversations (1:1 and group), messages, reactions, pins
+
+BEGIN;
+
+-- Unified conversations (1:1 or group)
+CREATE TABLE conversations (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(255),
+    is_group BOOLEAN NOT NULL DEFAULT FALSE,
+    owner_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMP NOT NULL DEFAULT NOW(),
+    last_message_id INTEGER  -- FK added below after conv_messages exists
+);
+
+CREATE INDEX idx_conversations_owner ON conversations(owner_id);
+CREATE INDEX idx_conversations_updated ON conversations(updated_at DESC);
+
+-- Conversation membership
+CREATE TABLE conversation_members (
+    conversation_id INTEGER NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
+    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    role VARCHAR(20) NOT NULL DEFAULT 'member',
+    last_read_at TIMESTAMP,
+    is_muted BOOLEAN NOT NULL DEFAULT FALSE,
+    is_archived BOOLEAN NOT NULL DEFAULT FALSE,
+    joined_at TIMESTAMP NOT NULL DEFAULT NOW(),
+    added_by_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+    PRIMARY KEY (conversation_id, user_id)
+);
+
+CREATE INDEX idx_conversation_members_user ON conversation_members(user_id);
+
+-- Messages within a conversation
+CREATE TABLE conv_messages (
+    id SERIAL PRIMARY KEY,
+    conversation_id INTEGER NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
+    sender_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+    content TEXT NOT NULL,
+    reply_to_id INTEGER REFERENCES conv_messages(id) ON DELETE SET NULL,
+    edited_at TIMESTAMP,
+    is_deleted BOOLEAN NOT NULL DEFAULT FALSE,
+    link_preview JSONB,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_conv_messages_conversation ON conv_messages(conversation_id);
+CREATE INDEX idx_conv_messages_created ON conv_messages(created_at);
+CREATE INDEX idx_conv_messages_conversation_created ON conv_messages(conversation_id, created_at);
+
+-- Now add the deferred FK from conversations.last_message_id -> conv_messages.id
+ALTER TABLE conversations
+    ADD CONSTRAINT fk_conversations_last_message
+    FOREIGN KEY (last_message_id) REFERENCES conv_messages(id) ON DELETE SET NULL;
+
+-- Emoji reactions on messages
+CREATE TABLE message_reactions (
+    id SERIAL PRIMARY KEY,
+    message_id INTEGER NOT NULL REFERENCES conv_messages(id) ON DELETE CASCADE,
+    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    emoji VARCHAR(10) NOT NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
+    CONSTRAINT uq_message_reaction UNIQUE (message_id, user_id, emoji)
+);
+
+CREATE INDEX idx_message_reactions_message ON message_reactions(message_id);
+
+-- Pinned messages
+CREATE TABLE message_pins (
+    id SERIAL PRIMARY KEY,
+    conversation_id INTEGER NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
+    message_id INTEGER NOT NULL REFERENCES conv_messages(id) ON DELETE CASCADE,
+    pinned_by_id INTEGER REFERENCES users(id) ON DELETE SET NULL,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_message_pins_conversation ON message_pins(conversation_id);
+
+-- Extend message_attachments to support conv_messages
+ALTER TABLE message_attachments ADD COLUMN conv_message_id INTEGER REFERENCES conv_messages(id) ON DELETE CASCADE;
+CREATE INDEX idx_message_attachments_conv ON message_attachments(conv_message_id) WHERE conv_message_id IS NOT NULL;
+
+-- Grants
+GRANT ALL ON TABLE conversations TO nordabiz_app;
+GRANT ALL ON TABLE conversation_members TO nordabiz_app;
+GRANT ALL ON TABLE conv_messages TO nordabiz_app;
+GRANT ALL ON TABLE message_reactions TO nordabiz_app;
+GRANT ALL ON TABLE message_pins TO nordabiz_app;
+GRANT USAGE, SELECT ON SEQUENCE conversations_id_seq TO nordabiz_app;
+GRANT USAGE, SELECT ON SEQUENCE conv_messages_id_seq TO nordabiz_app;
+GRANT USAGE, SELECT ON SEQUENCE message_reactions_id_seq TO nordabiz_app;
+GRANT USAGE, SELECT ON SEQUENCE message_pins_id_seq TO nordabiz_app;
+
+COMMIT;