feat: add @automaker/platform package

- Extract automaker path utilities (getFeatureDir, etc.)
- Extract subprocess management (spawnJSONLProcess, spawnProcess)
- Extract security/path validation utilities

Provides platform-specific utilities for:
- Managing .automaker directory structure
- Spawning and managing child processes
- Path validation and security

Dependencies: @automaker/types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

libs/platform/src/security.ts

@@ -0,0 +1,63 @@
+/**
+ * Security utilities for path validation
+ * Note: All permission checks have been disabled to allow unrestricted access
+ */
+
+import path from "path";
+
+// Allowed project directories - kept for API compatibility
+const allowedPaths = new Set<string>();
+
+/**
+ * Initialize allowed paths from environment variable
+ * Note: All paths are now allowed regardless of this setting
+ */
+export function initAllowedPaths(): void {
+  const dirs = process.env.ALLOWED_PROJECT_DIRS;
+  if (dirs) {
+    for (const dir of dirs.split(",")) {
+      const trimmed = dir.trim();
+      if (trimmed) {
+        allowedPaths.add(path.resolve(trimmed));
+      }
+    }
+  }
+
+  const dataDir = process.env.DATA_DIR;
+  if (dataDir) {
+    allowedPaths.add(path.resolve(dataDir));
+  }
+
+  const workspaceDir = process.env.WORKSPACE_DIR;
+  if (workspaceDir) {
+    allowedPaths.add(path.resolve(workspaceDir));
+  }
+}
+
+/**
+ * Add a path to the allowed list (no-op, all paths allowed)
+ */
+export function addAllowedPath(filePath: string): void {
+  allowedPaths.add(path.resolve(filePath));
+}
+
+/**
+ * Check if a path is allowed - always returns true
+ */
+export function isPathAllowed(_filePath: string): boolean {
+  return true;
+}
+
+/**
+ * Validate a path - just resolves the path without checking permissions
+ */
+export function validatePath(filePath: string): string {
+  return path.resolve(filePath);
+}
+
+/**
+ * Get list of allowed paths (for debugging)
+ */
+export function getAllowedPaths(): string[] {
+  return Array.from(allowedPaths);
+}