refactor: consolidate shared packages and eliminate code duplication

- Update 26+ files to import secureFs from @automaker/platform
- Create shared type files: github.ts, worktree.ts, claude.ts in libs/types
- Create exec-utils.ts for cross-platform shell execution
- Delete redundant wrapper files: secure-fs.ts, stream-processor.ts, enhancement-prompts.ts
- Update GitHub routes to use createLogError pattern
- Add isENOENT helper to routes/common.ts
- Fix test imports to use @automaker/prompts and @automaker/platform

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

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

apps/server/src/services/feature-loader.ts

@@ -7,12 +7,12 @@ import path from 'path';
 import type { Feature, PlanSpec, FeatureStatus } from '@automaker/types';
 import { createLogger } from '@automaker/utils';
 import { resolveDependencies, areDependenciesSatisfied } from '@automaker/dependency-resolver';
-import * as secureFs from '../lib/secure-fs.js';
 import {
   getFeaturesDir,
   getFeatureDir,
   getFeatureImagesDir,
   ensureAutomakerDir,
+  secureFs,
 } from '@automaker/platform';
 
 const logger = createLogger('FeatureLoader');