feat: cross-platform support with Node.js scripts

- Rewrite all bash hooks to Node.js for Windows/macOS/Linux compatibility
- Add package manager auto-detection (npm, pnpm, yarn, bun)
- Add scripts/lib/ with cross-platform utilities
- Add /setup-pm command for package manager configuration
- Add comprehensive test suite (62 tests)

Co-authored-by: zerx-lab

scripts/hooks/session-start.js

@@ -0,0 +1,61 @@
+#!/usr/bin/env node
+/**
+ * SessionStart Hook - Load previous context on new session
+ *
+ * Cross-platform (Windows, macOS, Linux)
+ *
+ * Runs when a new Claude session starts. Checks for recent session
+ * files and notifies Claude of available context to load.
+ */
+
+const path = require('path');
+const {
+  getSessionsDir,
+  getLearnedSkillsDir,
+  findFiles,
+  ensureDir,
+  log
+} = require('../lib/utils');
+const { getPackageManager, getSelectionPrompt } = require('../lib/package-manager');
+
+async function main() {
+  const sessionsDir = getSessionsDir();
+  const learnedDir = getLearnedSkillsDir();
+
+  // Ensure directories exist
+  ensureDir(sessionsDir);
+  ensureDir(learnedDir);
+
+  // Check for recent session files (last 7 days)
+  const recentSessions = findFiles(sessionsDir, '*.tmp', { maxAge: 7 });
+
+  if (recentSessions.length > 0) {
+    const latest = recentSessions[0];
+    log(`[SessionStart] Found ${recentSessions.length} recent session(s)`);
+    log(`[SessionStart] Latest: ${latest.path}`);
+  }
+
+  // Check for learned skills
+  const learnedSkills = findFiles(learnedDir, '*.md');
+
+  if (learnedSkills.length > 0) {
+    log(`[SessionStart] ${learnedSkills.length} learned skill(s) available in ${learnedDir}`);
+  }
+
+  // Detect and report package manager
+  const pm = getPackageManager();
+  log(`[SessionStart] Package manager: ${pm.name} (${pm.source})`);
+
+  // If package manager was detected via fallback, show selection prompt
+  if (pm.source === 'fallback' || pm.source === 'default') {
+    log('[SessionStart] No package manager preference found.');
+    log(getSelectionPrompt());
+  }
+
+  process.exit(0);
+}
+
+main().catch(err => {
+  console.error('[SessionStart] Error:', err.message);
+  process.exit(0); // Don't block on errors
+});