refactor: simplify hook execution - use Node directly instead of Bun (#290)

Removes bun-wrapper indirection. Hooks are compiled JavaScript that work perfectly with Node. Worker still uses Bun where performance matters. Fixes #264

src/utils/bun-path.ts

@@ -0,0 +1,77 @@
+/**
+ * Bun Path Utility
+ * 
+ * Resolves the Bun executable path for environments where Bun is not in PATH
+ * (e.g., fish shell users where ~/.config/fish/config.fish isn't read by /bin/sh)
+ */
+
+import { spawnSync } from 'child_process';
+import { existsSync } from 'fs';
+import { join } from 'path';
+import { homedir } from 'os';
+
+/**
+ * Get the Bun executable path
+ * Tries PATH first, then checks common installation locations
+ * Returns absolute path if found, null otherwise
+ */
+export function getBunPath(): string | null {
+  const isWindows = process.platform === 'win32';
+
+  // Try PATH first
+  try {
+    const result = spawnSync('bun', ['--version'], {
+      encoding: 'utf-8',
+      stdio: ['pipe', 'pipe', 'pipe'],
+      shell: isWindows
+    });
+    if (result.status === 0) {
+      return 'bun'; // Available in PATH
+    }
+  } catch {
+    // Not in PATH, continue to check common locations
+  }
+
+  // Check common installation paths
+  const bunPaths = isWindows
+    ? [join(homedir(), '.bun', 'bin', 'bun.exe')]
+    : [
+        join(homedir(), '.bun', 'bin', 'bun'),
+        '/usr/local/bin/bun',
+        '/opt/homebrew/bin/bun', // Apple Silicon Homebrew
+        '/home/linuxbrew/.linuxbrew/bin/bun' // Linux Homebrew
+      ];
+
+  for (const bunPath of bunPaths) {
+    if (existsSync(bunPath)) {
+      return bunPath;
+    }
+  }
+
+  return null;
+}
+
+/**
+ * Get the Bun executable path or throw an error
+ * Use this when Bun is required for operation
+ */
+export function getBunPathOrThrow(): string {
+  const bunPath = getBunPath();
+  if (!bunPath) {
+    const isWindows = process.platform === 'win32';
+    const installCmd = isWindows
+      ? 'powershell -c "irm bun.sh/install.ps1 | iex"'
+      : 'curl -fsSL https://bun.sh/install | bash';
+    throw new Error(
+      `Bun is required but not found. Install it with:\n  ${installCmd}\nThen restart your terminal.`
+    );
+  }
+  return bunPath;
+}
+
+/**
+ * Check if Bun is available (in PATH or common locations)
+ */
+export function isBunAvailable(): boolean {
+  return getBunPath() !== null;
+}