release: 2.0.0 — the agent harness operating system

Graduate 2.0.0-rc.1 to stable. Bump version across package, plugin,
marketplace, OpenCode, agent metadata, VERSION, and all localized docs.
Add 2.0.0 release notes + README sections (en/zh/pt-BR/tr), CHANGELOG
entry, and the ECC community Discord bot (dependency-free gateway client
+ guild command registrar). Update copilot-support and release-surface
tests for the sponsored-review migration and the 2.0.0 surface.

scripts/discord/register-commands.mjs

@@ -0,0 +1,38 @@
+#!/usr/bin/env node
+// Registers the ECC bot's guild slash commands (bulk overwrite, instant).
+// Env: DISCORD_BOT_TOKEN, DISCORD_APP_ID, DISCORD_GUILD_ID
+'use strict';
+
+const { DISCORD_BOT_TOKEN: TOKEN, DISCORD_APP_ID: APP_ID, DISCORD_GUILD_ID: GUILD } = process.env;
+if (!TOKEN || !APP_ID || !GUILD) {
+  console.error('missing DISCORD_BOT_TOKEN / DISCORD_APP_ID / DISCORD_GUILD_ID');
+  process.exit(1);
+}
+
+const COMMANDS = [
+  { name: 'ecc', description: 'What ECC is + all the links' },
+  { name: 'help', description: 'List ECC bot commands' },
+  {
+    name: 'skill',
+    description: 'Look up an ECC skill by name',
+    options: [{ type: 3, name: 'name', description: 'skill name or keyword', required: true }],
+  },
+  {
+    name: 'docs',
+    description: 'Search the ECC docs',
+    options: [{ type: 3, name: 'query', description: 'search terms', required: true }],
+  },
+  { name: 'release', description: 'Latest ECC release' },
+];
+
+const res = await fetch(`https://discord.com/api/v10/applications/${APP_ID}/guilds/${GUILD}/commands`, {
+  method: 'PUT',
+  headers: { Authorization: `Bot ${TOKEN}`, 'Content-Type': 'application/json' },
+  body: JSON.stringify(COMMANDS),
+});
+if (!res.ok) {
+  console.error('registration failed:', res.status, (await res.text()).slice(0, 300));
+  process.exit(1);
+}
+const registered = await res.json();
+console.log('registered:', registered.map(c => `/${c.name}`).join(' '));