fix: migrate hooks to stdin JSON input, fix duplicate main() calls, add threshold validation

- Migrate session-end.js and evaluate-session.js from CLAUDE_TRANSCRIPT_PATH
  env var to stdin JSON transcript_path (correct hook input mechanism)
- Remove duplicate main() calls that ran before stdin was read, causing
  session files to be created with empty data
- Add range validation (1-10000) on COMPACT_THRESHOLD in suggest-compact.js
  to prevent negative or absurdly large thresholds
- Add integration/hooks.test.js to tests/run-all.js so CI runs all 97 tests
- Update evaluate-session.sh to parse transcript_path from stdin JSON
- Update hooks.test.js to pass transcript_path via stdin instead of env var
- Sync .cursor/ copies

tests/run-all.js

@@ -13,7 +13,8 @@ const testsDir = __dirname;
 const testFiles = [
   'lib/utils.test.js',
   'lib/package-manager.test.js',
-  'hooks/hooks.test.js'
+  'hooks/hooks.test.js',
+  'integration/hooks.test.js'
 ];
 
 console.log('╔══════════════════════════════════════════════════════════╗');