## Why
Config loading should not create or write-authorize the memories root
just because memory support exists. Memory startup is the code path that
actually materializes that tree.
## What
- Stop creating the memories root during Config load and remove it from
legacy workspace-write projections.
- Grant the memories root read access only when the memories feature and
use_memories are enabled.
- Create the memories root inside memories startup before seeding
extension instructions.
- Update config and startup tests around the ownership boundary.
## Tests
- just fmt
- just fix -p codex-core
- just fix -p codex-memories-write
- just test -p codex-core
memory_tool_makes_memories_root_readable_without_creating_or_widening_writes
workspace_write_includes_configured_writable_root_once_without_memories_root
permission_profile_override_keeps_memories_root_out_of_legacy_projection
permissions_profiles_allow_direct_write_roots_outside_workspace_root
default_permissions_profile_populates_runtime_sandbox_policy
- just test -p codex-memories-write memories_startup_creates_memory_root
Note: a broader just test -p codex-core run is not clean in this
sandbox; it hit missing test_stdio_server plus seatbelt, realtime, and
environment-sensitive failures. The changed config tests above pass.
jif-oai
d5ec93f379