Session Memory Path Refactoring

What: Session memory now uses project-based paths instead of global paths, with centralized helper functions.

Details:

• New path: <project-dir>/<session-id>/session-memory/ instead of <global-config>/session-memory/
• Three new helpers: zI1() (base path), _B1() (summary.md path), zP3() (path check)
• New summary.md file with structured template (Task specification, Files and Functions, Workflow, etc.)
• Better isolation between projects and sessions
• Evidence: zI1() at line 506034, _B1() at line 506037, jG2() summary reader at line 340819