refactor: extract inline PostToolUse hooks into external scripts

Move three complex inline hooks from hooks.json into proper external
scripts in scripts/hooks/:

- post-edit-format.js: Prettier auto-formatting (was 1 minified line)
- post-edit-typecheck.js: TypeScript check (was 1 minified line with
  unbounded directory traversal, now capped at 20 levels)
- post-edit-console-warn.js: console.log warnings (was 1 minified line)

Benefits:
- Readable, documented, and properly error-handled
- Testable independently via stdin
- Consistent with other hooks (all use external scripts now)
- Adds timeouts to Prettier (15s) and tsc (30s) to prevent hangs

scripts/hooks/post-edit-format.js

@@ -0,0 +1,40 @@
+#!/usr/bin/env node
+/**
+ * PostToolUse Hook: Auto-format JS/TS files with Prettier after edits
+ *
+ * Cross-platform (Windows, macOS, Linux)
+ *
+ * Runs after Edit tool use. If the edited file is a JS/TS file,
+ * formats it with Prettier. Fails silently if Prettier isn't installed.
+ */
+
+const { execFileSync } = require('child_process');
+const fs = require('fs');
+
+let data = '';
+
+process.stdin.on('data', chunk => {
+  data += chunk;
+});
+
+process.stdin.on('end', () => {
+  try {
+    const input = JSON.parse(data);
+    const filePath = input.tool_input?.file_path;
+
+    if (filePath && /\.(ts|tsx|js|jsx)$/.test(filePath) && fs.existsSync(filePath)) {
+      try {
+        execFileSync('npx', ['prettier', '--write', filePath], {
+          stdio: ['pipe', 'pipe', 'pipe'],
+          timeout: 15000
+        });
+      } catch {
+        // Prettier not installed or failed — non-blocking
+      }
+    }
+  } catch {
+    // Invalid input — pass through
+  }
+
+  console.log(data);
+});