feat: add Cursor, Codex, and OpenCode harnesses — maximize every AI coding tool

- AGENTS.md: universal cross-tool file read by Claude Code, Cursor, Codex, and OpenCode
- .cursor/: 15 hook events via hooks.json, 16 hook scripts with DRY adapter pattern,
  29 rules (9 common + 20 language-specific) with Cursor YAML frontmatter
- .codex/: reference config.toml, Codex-specific AGENTS.md supplement,
  10 skills ported to .agents/skills/ with openai.yaml metadata
- .opencode/: 3 new tools (format-code, lint-check, git-summary), 3 new hooks
  (shell.env, experimental.session.compacting, permission.ask), expanded instructions,
  version bumped to 1.6.0
- README: fixed Cursor section, added Codex section, added cross-tool parity table
- install.sh: now copies hooks.json + hooks/ for --target cursor

.cursor/hooks/after-shell-execution.js

@@ -0,0 +1,26 @@
+#!/usr/bin/env node
+const { readStdin } = require('./adapter');
+readStdin().then(raw => {
+  try {
+    const input = JSON.parse(raw);
+    const cmd = input.command || '';
+    const output = input.output || input.result || '';
+
+    // PR creation logging
+    if (/gh pr create/.test(cmd)) {
+      const m = output.match(/https:\/\/github\.com\/[^/]+\/[^/]+\/pull\/\d+/);
+      if (m) {
+        console.error('[ECC] PR created: ' + m[0]);
+        const repo = m[0].replace(/https:\/\/github\.com\/([^/]+\/[^/]+)\/pull\/\d+/, '$1');
+        const pr = m[0].replace(/.+\/pull\/(\d+)/, '$1');
+        console.error('[ECC] To review: gh pr review ' + pr + ' --repo ' + repo);
+      }
+    }
+
+    // Build completion notice
+    if (/(npm run build|pnpm build|yarn build)/.test(cmd)) {
+      console.error('[ECC] Build completed');
+    }
+  } catch {}
+  process.stdout.write(raw);
+}).catch(() => process.exit(0));