feat(phase4): rich profiles, badges DB, block list

internal/db/db.go

@@ -344,6 +344,42 @@ ALTER TABLE channels ADD COLUMN IF NOT EXISTS message_count INTEGER NOT NULL DEF
 ALTER TABLE channels ADD COLUMN IF NOT EXISTS last_message_at TIMESTAMPTZ;
 CREATE INDEX IF NOT EXISTS idx_channels_parent ON channels(parent_channel_id);
 
+ALTER TABLE users ADD COLUMN IF NOT EXISTS banner_url TEXT;
+ALTER TABLE users ADD COLUMN IF NOT EXISTS tagline VARCHAR(128);
+ALTER TABLE users ADD COLUMN IF NOT EXISTS social_links JSONB DEFAULT '[]';
+ALTER TABLE users ADD COLUMN IF NOT EXISTS pronouns VARCHAR(40);
+
+-- Badges
+CREATE TABLE IF NOT EXISTS badges (
+	id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+	server_id UUID REFERENCES servers(id) ON DELETE CASCADE,
+	name VARCHAR(64) NOT NULL,
+	icon TEXT,
+	description TEXT,
+	created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_badges_server ON badges(server_id);
+
+CREATE TABLE IF NOT EXISTS user_badges (
+	user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+	badge_id UUID NOT NULL REFERENCES badges(id) ON DELETE CASCADE,
+	granted_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+	granted_by UUID REFERENCES users(id) ON DELETE SET NULL,
+	PRIMARY KEY (user_id, badge_id)
+);
+
+-- Block list
+CREATE TABLE IF NOT EXISTS blocks (
+	blocker_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+	blocked_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+	created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+	PRIMARY KEY (blocker_id, blocked_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_blocks_blocker ON blocks(blocker_id);
+CREATE INDEX IF NOT EXISTS idx_blocks_blocked ON blocks(blocked_id);
+
 -- Message full-text search
 ALTER TABLE messages ADD COLUMN IF NOT EXISTS search_vector tsvector;
 CREATE INDEX IF NOT EXISTS idx_messages_search ON messages USING GIN(search_vector);