feat: /snippet code sharing command (#41)

migrations/004_snippets.cjs

@@ -0,0 +1,33 @@
+/**
+ * Add snippets table for /snippet code sharing command.
+ * Stores named code snippets per guild with syntax-highlighted retrieval.
+ *
+ * @see https://github.com/VolvoxLLC/volvox-bot/issues/41
+ */
+
+/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
+exports.up = (pgm) => {
+  pgm.sql(`
+    CREATE TABLE IF NOT EXISTS snippets (
+      id SERIAL PRIMARY KEY,
+      guild_id TEXT NOT NULL,
+      name TEXT NOT NULL,
+      language TEXT NOT NULL DEFAULT 'text',
+      code TEXT NOT NULL,
+      description TEXT,
+      author_id TEXT NOT NULL,
+      usage_count INTEGER NOT NULL DEFAULT 0,
+      created_at TIMESTAMPTZ DEFAULT NOW(),
+      updated_at TIMESTAMPTZ DEFAULT NOW(),
+      UNIQUE(guild_id, name)
+    )
+  `);
+
+  pgm.sql('CREATE INDEX IF NOT EXISTS idx_snippets_guild ON snippets(guild_id)');
+  pgm.sql('CREATE INDEX IF NOT EXISTS idx_snippets_name ON snippets(guild_id, name)');
+};
+
+/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
+exports.down = (pgm) => {
+  pgm.sql('DROP TABLE IF EXISTS snippets CASCADE');
+};