BOOTMAP-BOOTROOT-FIX (E-074): the domain boot-map boot_root is pinned to the project root, decoupled from --gc-path/CWD. v0.4.43 sealed its baseline against the project root and audits against p.parent.parent, but cmd_session_start derived boot_root from --gc-path (default Path('.') always truthy, so the intended else rag_dir.parent branch was dead) -- run from RAG/ it diffed RAG-relative paths against a project-root-keyed baseline, emitting spurious +N/-M boot churn (cosmetic; session_start_line is READ-ONLY, the persisted seal was always correct). boot_root is now unconditionally rag_dir.parent; --gc-path governs only the GC scan. +regression test test_session_start_bootmap_root_is_project_root_not_gcpath. No schema/WAL/TLA+ change (drift gate 268149294421); health 21/21; suite 2001 -> 2002 green.