feat: add discord-guilds skill with table merge on install

skills/discord-guilds/scripts/add-guild

@@ -0,0 +1,56 @@
+#!/usr/bin/env node
+/**
+ * Add a guild entry to the discord-guilds SKILL.md table
+ * Usage: add-guild <guild-id> <description>
+ */
+
+import fs from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const SKILL_PATH = path.resolve(__dirname, "../SKILL.md");
+
+function main() {
+  const args = process.argv.slice(2);
+  
+  if (args.length < 2) {
+    console.error("Usage: add-guild <guild-id> <description>");
+    process.exit(1);
+  }
+  
+  const guildId = args[0];
+  const description = args.slice(1).join(" ");
+  
+  // Validate guild ID is numeric
+  if (!/^\d+$/.test(guildId)) {
+    console.error("Error: guild-id must be numeric (Discord snowflake)");
+    process.exit(1);
+  }
+  
+  // Read existing SKILL.md
+  let content = fs.readFileSync(SKILL_PATH, "utf8");
+  
+  // Find the table and insert new row
+  const newRow = `| ${guildId} | ${description} |`;
+  
+  // Look for the table pattern and insert after the header
+  const tablePattern = /(\| guild-id \| description \|\n\|[-\s|]+\|)/;
+  
+  if (!tablePattern.test(content)) {
+    console.error("Error: Could not find guild table in SKILL.md");
+    process.exit(1);
+  }
+  
+  // Insert new row after the table header
+  content = content.replace(tablePattern, `$1\n${newRow}`);
+  
+  // Write back
+  fs.writeFileSync(SKILL_PATH, content, "utf8");
+  
+  console.log(`✓ Added guild: ${guildId} - ${description}`);
+}
+
+main();